WO2022209534A1 - Catalyst composition for exhaust gas purification and catalyst for exhaust gas purification - Google Patents

Catalyst composition for exhaust gas purification and catalyst for exhaust gas purification Download PDF

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Publication number
WO2022209534A1
WO2022209534A1 PCT/JP2022/008674 JP2022008674W WO2022209534A1 WO 2022209534 A1 WO2022209534 A1 WO 2022209534A1 JP 2022008674 W JP2022008674 W JP 2022008674W WO 2022209534 A1 WO2022209534 A1 WO 2022209534A1
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Prior art keywords
exhaust gas
mass
oxide particles
based oxide
catalyst composition
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PCT/JP2022/008674
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French (fr)
Japanese (ja)
Inventor
格 森田
裕樹 田中
有希 永尾
慶徳 遠藤
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三井金属鉱業株式会社
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Application filed by 三井金属鉱業株式会社 filed Critical 三井金属鉱業株式会社
Priority to EP22779759.4A priority Critical patent/EP4316654A1/en
Priority to JP2023510307A priority patent/JP7284362B2/en
Priority to US18/284,714 priority patent/US20240149252A1/en
Priority to CN202280025327.7A priority patent/CN117083122A/en
Publication of WO2022209534A1 publication Critical patent/WO2022209534A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N3/00—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust
    • F01N3/08—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous
    • F01N3/10—Exhaust or silencing apparatus having means for purifying, rendering innocuous, or otherwise treating exhaust for rendering innocuous by thermal or catalytic conversion of noxious components of exhaust
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    • B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/34—Chemical or biological purification of waste gases
    • B01D53/92—Chemical or biological purification of waste gases of engine exhaust gases
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    • B01D53/34—Chemical or biological purification of waste gases
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    • B01D53/9445—Simultaneously removing carbon monoxide, hydrocarbons or nitrogen oxides making use of three-way catalysts [TWC] or four-way-catalysts [FWC]
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Definitions

  • the present invention relates to an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst.
  • Exhaust gases emitted from internal combustion engines such as automobiles and motorcycles contain harmful components such as hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx).
  • THC hydrocarbons
  • CO carbon monoxide
  • NOx nitrogen oxides
  • a three-way catalyst is used.
  • Al-based oxides such as alumina (Al 2 O 3 ), Ce—Zr system composite oxides and the like are used (for example, Patent Documents 1 and 2).
  • Al-based oxide means an oxide containing Al
  • the amount of Al converted to Al 2 O 3 is 70% by mass or more based on the mass of the oxide.
  • Ce-Zr-based composite oxide is a composite oxide containing Ce and Zr, and the amount of Ce converted to CeO2 is 5 mass% or more and 90 mass% or less based on the mass of the composite oxide. means a composite oxide.
  • a Ce—Zr-based composite oxide is a material (OSC material) having an oxygen storage capacity (OSC), and mitigates fluctuations in the oxygen concentration in the exhaust gas to expand the operating window of the catalyst.
  • Ce-based oxides such as cerium oxide (CeO 2 ) are also used as OSC materials (for example, Patent Document 2).
  • CeO 2 has a low oxygen storage capacity, it is generally not used as a carrier for supporting catalytically active components of a three-way catalyst.
  • the term "Ce-based oxide” means an oxide containing Ce and having a CeO2 equivalent amount of Ce of 80% by mass or more based on the mass of the oxide.
  • Ce-based oxides have a high affinity for catalytically active components (for example, precious metal particles such as Pt, Pd, and Rh), but have low heat resistance.
  • Ce—Zr-based composite oxides have high heat resistance, but relatively low affinity for catalytically active components (for example, particles of noble metals such as Pt, Pd, and Rh). Therefore, by using both a Ce-based oxide and a Ce--Zr-based composite oxide as a carrier for supporting a catalytically active component, the weak points of one can be compensated for by the other. However, even if a Ce-based oxide and a Ce--Zr-based composite oxide are used in combination, the exhaust gas purification performance may be lowered.
  • CeO2 when CeO2 is used as a support for supporting a catalytically active component, due to the low heat resistance of CeO2, CeO2 aggregates with each other, disappearance of small pores in CeO2 ( i.e., decrease in specific surface area ), etc., may occur, which may lead to the burial of the catalytically active component, thereby degrading the exhaust gas purification performance. Aggregation of CeO 2 and reduction in the specific surface area of CeO 2 are likely to occur in a high temperature environment, and thus deterioration in exhaust gas purification performance is likely to occur after exposure to a high temperature environment.
  • "high temperature” means a temperature of, for example, 800°C or higher, particularly 900°C or higher.
  • the exhaust gas purification performance may decrease due to the low oxygen storage capacity of CeO 2 .
  • the present invention provides an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst using a Ce-based oxide and a Ce—Zr-based composite oxide, which have exhaust gas purifying performance (especially after being exposed to a high-temperature environment
  • An object of the present invention is to provide an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst with improved exhaust gas purifying performance.
  • the present inventors have found that in a catalyst composition for purifying an exhaust gas and a catalyst for purifying an exhaust gas using a Ce-based oxide and a Ce—Zr-based composite oxide, Al, Mg, La, Pr, Y and Nd are added to the Ce-based oxide. It has been found that the addition of at least one additional element selected from is improved in exhaust gas purification performance, especially after exposure to a high temperature environment.
  • the present invention is an invention completed based on the above findings, and includes the following inventions.
  • An exhaust gas purifying catalyst composition containing Ce-based oxide particles, Ce--Zr-based mixed oxide particles, and a noble metal element,
  • the Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y and Nd,
  • the CeO 2 equivalent amount of Ce in the Ce-based oxide particles is 80% by mass or more based on the mass of the Ce-based oxide particles,
  • the amount of the at least one additional element in the Ce-based oxide particles in terms of oxide is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide particles
  • a catalyst composition for exhaust gas purification wherein the CeO 2 equivalent amount of Ce in the Ce—Zr-based mixed oxide particles is 5% by mass or more and 90% by mass or less based on the mass of the Ce—Zr-based mixed oxide particles.
  • An exhaust gas purification catalyst comprising a substrate and a catalyst layer provided on the substrate, An exhaust gas purifying catalyst, wherein the catalyst layer is composed of the exhaust gas purifying catalyst composition
  • an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst using a Ce-based oxide and a Ce—Zr-based composite oxide which have an exhaust gas purifying performance (in particular, exhaust gas purifying after exposure to a high temperature environment
  • an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst with improved performance are provided.
  • FIG. 1 is a partial end view showing a state in which an exhaust gas purifying catalyst according to a first embodiment of the present invention is arranged in an exhaust passage of an internal combustion engine.
  • FIG. 2 is an end view taken along the line AA of FIG. 1.
  • FIG. 3 is an enlarged view of the area indicated by symbol R in FIG. 4 is an end view taken along the line BB of FIG. 1.
  • FIG. FIG. 5 is an end view (end view corresponding to FIG. 4) of the exhaust gas purifying catalyst according to the second embodiment of the present invention.
  • the exhaust gas purifying catalyst composition of the present invention contains Ce-based oxide particles.
  • Ce-based oxide particles means Ce-based oxide particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified. It is distinguished from the Ce-based oxide particles used as a raw material of the catalyst composition for industrial use (hereinafter referred to as "Ce-based oxide particles as a raw material").
  • the Ce-based oxide particles are composed of a Ce-based oxide.
  • the CeO2 equivalent amount of Ce in the Ce-based oxide particles is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the mass of the Ce-based oxide particles. .
  • This improves the affinity of the Ce-based oxide particles for the catalytically active component, and suppresses the occurrence of sintering between the catalytically active components carried on the Ce-based oxide particles. Therefore, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved. Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment.
  • the upper limit is a value obtained by subtracting the amount of the additional element in terms of oxide from 100% by mass.
  • the CeO 2 equivalent amount of Ce in the Ce-based oxide particles is obtained by analyzing a sample obtained from the exhaust gas purification catalyst composition of the present invention by energy dispersive X-ray spectroscopy (EDS (also called EDX)). It can be determined from direct elemental mapping and EDS elemental analysis of specified particles. Specifically, by qualitatively identifying (color-coding) Ce-based oxide particles, Ce—Zr-based mixed oxide particles and other particles (for example, Al-based oxide particles) by elemental mapping, By performing a composition analysis (elemental analysis) with the specified particle, the oxide-equivalent amount of the predetermined element in the specified particles can be measured.
  • EDS energy dispersive X-ray spectroscopy
  • Ce-based oxide particles from the viewpoint of further improving the affinity of the Ce-based oxide particles for the catalytically active component and more effectively suppressing the occurrence of sintering between the catalytically active components supported on the Ce-based oxide particles. is preferably less than 10% by mass, more preferably 5% by mass or less, even more preferably 3% by mass or less, still more preferably 1% by mass, based on the mass of the Ce - based oxide particles. % or less.
  • the lower bound is zero.
  • the ZrO 2 equivalent amount of Zr in the Ce-based oxide particles is smaller than the ZrO 2 equivalent amount of Zr in the Ce—Zr-based composite oxide particles. distinguished from matter particles.
  • the method for measuring the ZrO2 equivalent amount of Zr in the Ce - based oxide particles is the same as the method for measuring the CeO2 equivalent amount of Ce in the Ce - based oxide particles.
  • the Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y and Nd. That is, the Ce-based oxide particles are composite oxides containing Ce and at least one additional element selected from Al, Mg, La, Pr, Y and Nd.
  • the "additional element” means an element other than Ce and O.
  • the additional element may form a solid solution phase with Ce and O, may form a single phase that is a crystalline phase or an amorphous phase (for example, an oxide phase of the additional element), or may form a solid solution Both phases and single phases may be formed.
  • the Ce-based oxide particles contain at least one additional element selected from Al and Mg
  • the heat resistance of the Ce-based oxide particles is improved, the specific surface area of the Ce-based oxide particles is reduced, and the associated Ce-based
  • the burial of the catalytically active component in the oxide particles is suppressed. Therefore, the specific surface area of the exhaust gas purifying catalyst composition is improved, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purifying performance of the exhaust gas purifying catalyst composition is improved.
  • Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment. This is because the decrease in the specific surface area of the Ce-based oxide particles and the accompanying burial of the catalytically active component in the Ce-based oxide particles tend to occur after exposure to a high-temperature environment.
  • the oxygen storage capacity of the Ce-based oxide particles after supporting the noble metal element i.e., the oxygen concentration in the exhaust gas is
  • the oxygen concentration in the exhaust gas is low, the ability to store oxygen is improved. Therefore, fluctuations in the oxygen concentration in the exhaust gas are mitigated, the operating window of the catalytically active component is expanded, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved.
  • the oxide conversion amount of the additional element in the Ce-based oxide particles is preferably 0.1% by mass or more based on the mass of the Ce-based oxide particles. % by mass or less.
  • “Additional elements in terms of oxides” are Al 2 O 3 equivalents for Al, MgO equivalents for Mg, La 2 O 3 equivalents for La, and Pr 6 O 11 equivalents for Pr.
  • Y means the Y 2 O 3 equivalent amount
  • Nd means the Nd 2 O 3 equivalent amount.
  • the "oxide equivalent amount of additional element” means the oxide equivalent amount of the one additional element when the Ce-based oxide particles contain one additional element, and the Ce-based oxide particles When two or more additional elements are included, it means the sum of the oxide-equivalent amounts of the two or more additional elements.
  • the total amount of Ce in terms of CeO2 and the amount of additional elements in terms of oxides in the Ce-based oxide particles is preferably based on the mass of the Ce-based oxide particles. is 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass or more. In addition, an upper limit is 100 mass %.
  • first additional element the additional element selected from Al and Mg
  • second additional element the additional element selected from La, Pr, Y and Nd
  • the Ce-based oxide particles contain at least one first additional element and do not contain a second additional element.
  • the oxide conversion amount of the first additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, Preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 15% by mass or less, still more preferably 0.1% by mass or more and 12% by mass or less, still more preferably 0.1% by mass % or more and 10% by mass or less.
  • Oxide conversion amount of the first additional element means the oxide conversion amount of the first additional element when the Ce-based oxide particles contain the first additional element, and the Ce-based When the oxide particles contain two kinds of the first additional elements, it means the sum of the oxide-equivalent amounts of the two kinds of the first additional elements.
  • the Ce-based oxide particles contain at least one second additional element and do not contain the first additional element.
  • the oxide conversion amount of the second additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, Preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 15% by mass or less, still more preferably 0.1% by mass or more and 12% by mass or less, still more preferably 0.1% by mass % or more and 10% by mass or less.
  • Oxide conversion amount of the second additional element means the oxide conversion amount of the one type of second additional element when the Ce-based oxide particles contain one type of second additional element, and the Ce-based When the oxide particles contain two or more second additional elements, it means the sum of the oxide-equivalent amounts of the two or more second additional elements.
  • the Ce-based oxide particles contain at least one first additional element and at least one second additional element.
  • the oxide conversion amount of the first additional element in the Ce-based oxide particles is the mass of the Ce-based oxide particles.
  • the oxide conversion amount of the second additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, preferably 0.1% by mass or more and 19.9% by mass or less, more preferably 0.1% by mass or more and 14.9% by mass or less, still more preferably 0.1% by mass or more and 11.9% by mass or less, still more preferably It is 0.1% by mass or more and 9.9% by mass or less, and the total amount of oxide conversion of the first and second additional elements in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, preferably 0.2% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, even more preferably 1% by mass or more and
  • the crystallite size of CeO 2 in the Ce-based oxide particles is preferably 7 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and still more preferably 30 nm or more. This suppresses the aggregation of the Ce-based oxide particles, the disappearance of the small pores of the Ce-based oxide particles (that is, the decrease in the specific surface area), and the accompanying burial of the catalytically active component in the Ce-based oxide particles. . Therefore, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved. Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment.
  • the upper limit of the crystallite size of CeO 2 in the Ce-based oxide particles is, for example, 200 nm, preferably 100 nm, and more preferably 55 nm. Each of these upper limits may be combined with any of the above lower limits.
  • the method for measuring the crystallite size of CeO 2 in Ce-based oxide particles is as follows.
  • X-ray diffraction X-ray diffraction
  • the crystallite diameter of CeO 2 in the Ce-based oxide particles may be adjusted, for example, by adjusting the firing conditions when producing the Ce-based oxide particles, or by adjusting the crystallite size in the production stage of the Ce-based oxide particles. It may be adjusted by providing a curing step (eg, exposure to hydrothermal conditions, etc.).
  • the amount of the Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention should be equal to the mass of the exhaust gas purifying catalyst composition of the present invention.
  • a standard preferably 1.0% by mass or more, more preferably 2.0% by mass or more, even more preferably 3.0% by mass or more, still more preferably 5.0% by mass or more, and still more preferably 10% by mass % or more.
  • the amount of components other than Ce-based oxide particles is relatively increased, and the specific surface area of the exhaust gas purifying catalyst composition (in particular, from the viewpoint of further improving the specific surface area after exposure to a high temperature environment, the amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, still more preferably 20% by mass or less, and even more preferably 15% by mass or less.
  • the amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, still more preferably 20% by mass or less, and even more preferably 15% by mass or less.
  • Each of these upper limits may be combined with any of the above lower limits.
  • the amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is measured by the following procedures (A) to (D).
  • ICP inductively coupled plasma atomic emission spectrometry
  • XRF X-ray fluorescence spectrometry
  • SEM scanning electron microscope-energy dispersive X-ray spectrometry
  • (B) The sample obtained from the exhaust gas purification catalyst composition was subjected to SEM observation and elemental mapping by SEM-EDX, and the types of particles contained in the sample (Ce-based oxide particles, Ce-Zr-based composite oxide particles and other particles (including, for example, Al-based oxide particles).
  • each element in the sample, the content of each element in each type of particle, and the content of each type of particle in the sample by creating and solving an equation representing the relationship between the content of each element in the sample and the content of each type of particle in the sample Calculate the content of particles of each type.
  • the Ce source, Zr source, and Al source in the exhaust gas purifying catalyst composition of the present invention consist of only three types of Ce-based oxide particles, Ce—Zr-based composite oxide particles, and Al-based oxide particles
  • the amount of Ce-based oxide particles is determined as follows.
  • a sample obtained from the exhaust gas purifying catalyst composition of the present invention was subjected to SEM-EDX analysis for five arbitrarily selected fields of view (each field of view contains 20 or more particles), The types of constituent elements of the entire sample are specified, and the content rate (average value) of each specified element is obtained in terms of oxide.
  • the sample obtained from the exhaust gas purifying catalyst composition was subjected to SEM observation and elemental mapping by SEM-EDX, and the types of particles contained in the sample (Ce-based oxide particles, Ce—Zr-based composite oxide particles and Al-based oxide particles).
  • the average particle size of the Ce-based oxide particles is too small, a solid phase reaction proceeds at the interface between the Ce-based oxide particles and the Ce—Zr-based composite oxide particles, and the Ce-based oxide particles cannot exist as particles. .
  • a solid phase reaction at the interface between the Ce-based oxide particles and the Ce--Zr-based mixed oxide particles tends to occur after exposure to a high-temperature environment.
  • the average particle size of the Ce-based oxide particles is too large, the dispersibility of the Ce-based oxide particles is lowered, and the contact between the Ce-based oxide particles and the catalytically active component is lowered.
  • the average particle size of the Ce-based oxide particles is preferably 0.10 ⁇ m or more and 15 ⁇ m or less, more preferably 0.50 ⁇ m or more and 12 ⁇ m or less. , more preferably 1.0 ⁇ m or more and 10 ⁇ m or less, and still more preferably 2.0 ⁇ m or more and 7.0 ⁇ m or less.
  • the method for measuring the average particle size of Ce-based oxide particles is as follows. A sample obtained from the exhaust gas purifying catalyst composition of the present invention was observed using a scanning electron microscope, and 100 Ce-based oxide particles arbitrarily selected from the field of view had a directional diameter (Ferret diameter ) are measured, and the average value is taken as the average particle diameter of the Ce-based oxide particles.
  • the average particle size of the Ce-based oxide particles as a raw material is maintained. It is the same as the average particle size of Ce-based oxide particles.
  • the average particle size of the Ce-based oxide particles may be adjusted, for example, by using a known pulverization method such as a ball mill, or by using a granulation method such as a spray drying method when producing the Ce-based oxide particles. can be adjusted.
  • Ce-based oxide particles are used as carriers for catalytically active components. From the viewpoint of improving the supportability of the catalytically active component, the Ce-based oxide particles are preferably porous. Ce-based oxide particles are distinguished from ceria used as a binder (hereinafter referred to as "ceria binder").
  • the ceria binder is derived from a water-soluble cerium salt such as ceria sol or cerium nitrate or cerium nitrate used as a material for the catalyst composition.
  • the Ce-based oxide particles may contain one or more metal elements other than Ce, Al, Mg, La, Pr, Y and Nd.
  • metal elements other than Ce, Al, Mg, La, Pr, Y and Nd include rare earth elements such as Sc, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, Fe, Examples include transition metal elements such as Mn, Ni, and Zr.
  • Metal elements other than Ce, Al, Mg, La, Pr, Y, and Nd may form a solid solution phase with Ce and O, or may be a single phase that is a crystal phase or an amorphous phase (for example, metal elements oxide phase), or both a solid solution phase and a single phase may be formed.
  • the exhaust gas purifying catalyst composition of the present invention contains Ce—Zr composite oxide particles.
  • Ce--Zr-based composite oxide particles mean Ce--Zr-based composite oxide particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified.
  • Ce—Zr composite oxide particles used as raw materials for the exhaust gas purifying catalyst composition of the present invention hereinafter referred to as “Ce—Zr composite oxide particles as raw materials”.
  • the Ce—Zr-based composite oxide particles have an oxygen storage capacity (that is, the ability to store oxygen when the oxygen concentration in the exhaust gas is high, and to release oxygen when the oxygen concentration in the exhaust gas is low). It mitigates fluctuations in oxygen concentration and expands the operating window of catalytically active components. Therefore, the exhaust gas purifying ability of the exhaust gas purifying catalyst composition is improved.
  • the Ce—Zr-based composite oxide particles are composed of a Ce—Zr-based composite oxide.
  • the CeO 2 equivalent amount of Ce in the Ce—Zr-based composite oxide particles is preferably based on the mass of the Ce—Zr-based composite oxide particles. is 5% to 90% by mass, more preferably 5% to 70% by mass, even more preferably 7% to 60% by mass, and even more preferably 10% to 50% by mass.
  • the method for measuring the CeO 2 equivalent amount of Ce in the Ce—Zr-based mixed oxide particles is the same as the method for measuring the CeO 2 equivalent amount of Ce in the Ce-based oxide particles.
  • Ce- The ZrO2 equivalent amount of Zr in the Zr-based composite oxide particles is preferably 10% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 95% by mass, based on the mass of the Ce—Zr-based composite oxide particles. Below, it is more preferably 40% by mass or more and 95% by mass or less, and still more preferably 50% by mass or more and 90% by mass or less.
  • the method for measuring the ZrO 2 equivalent amount of Zr in the Ce—Zr-based composite oxide particles is the same as the method for measuring the CeO 2 equivalent amount of Ce in the Ce-based oxide particles.
  • the total amount of Ce in terms of CeO 2 and Zr in terms of ZrO 2 in the Ce—Zr-based mixed oxide particles is preferably 70% by mass or more, or more, based on the mass of the Ce—Zr-based mixed oxide particles. It is preferably 75% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more. The upper limit is 100% by mass.
  • the amount of the Ce—Zr-based composite oxide particles in the exhaust gas purifying catalyst composition of the present invention is Based on the weight of the catalyst composition, it is preferably 5% by weight or more, more preferably 15% by weight or more, and even more preferably 30% by weight or more.
  • the Ce—Zr-based composite in the exhaust gas purifying catalyst composition of the present invention is preferably 98.99% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, based on the mass of the exhaust gas purifying catalyst composition of the present invention. Each of these upper limits may be combined with any of the above lower limits.
  • the method for measuring the amount of Ce-Zr-based mixed oxide particles in the exhaust gas-purifying catalyst composition of the present invention is the same as the method for measuring the amount of Ce-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention.
  • the ratio of the amount of Ce—Zr-based composite oxide particles to the amount of Ce-based oxide particles is a mass ratio, preferably It is 0.5 or more and 70 or less, more preferably 1.0 or more and 25 or less, and still more preferably 1.5 or more and 15 or less.
  • the average particle size of the Ce—Zr-based composite oxide particles is preferably 0.1 ⁇ m or more and 15 ⁇ m or less, more preferably 0.5 ⁇ m or more and 12 ⁇ m or less, and still more preferably 1 ⁇ m or more and 10 ⁇ m or less.
  • the method for measuring the average particle size of the Ce—Zr-based composite oxide particles is the same as the method for measuring the average particle size of the Ce-based oxide particles.
  • the average particle size of the Ce—Zr-based composite oxide particles can be adjusted in the same manner as the average particle size of the Ce-based oxide particles.
  • the average particle size of the Ce—Zr-based mixed oxide particles as a raw material is maintained, the average particle size of the Ce—Zr-based mixed oxide particles is usually The diameter is the same as the average particle diameter of the Ce--Zr composite oxide particles as the raw material.
  • the Ce-Zr-based composite oxide particles are used as a carrier for catalytically active components. From the viewpoint of improving the supportability of the catalytically active component, the Ce—Zr-based composite oxide particles are preferably porous.
  • Ce, Zr, and O preferably form a solid solution phase in the Ce—Zr-based composite oxide particles.
  • Ce, Zr and O may form a single phase (CeO 2 phase and/or ZrO 2 phase), which is a crystalline phase or an amorphous phase, in addition to a solid solution phase.
  • the Ce—Zr-based composite oxide particles may contain one or more metal elements other than Ce and Zr.
  • Metal elements other than Ce and Zr include, for example, rare earth elements other than Ce. Examples of rare earth elements other than Ce include Y, Pr, Sc, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu.
  • Metal elements other than Ce and Zr, together with Ce, Zr and O, may form a solid solution phase, may form a single phase that is a crystalline phase or an amorphous phase, may form a solid solution phase and Both single phases may be formed.
  • the exhaust gas purifying catalyst composition of the present invention contains at least one precious metal element.
  • the noble metal element can be selected from, for example, Au, Ag, Pt, Pd, Rh, Ir, Ru, Os, etc., and is preferably selected from Rh and Pt.
  • the noble metal element is in a form capable of functioning as a catalytically active component, such as a metal, an alloy containing a noble metal element, a compound containing a noble metal element (e.g., an oxide of a noble metal element), and the like, in the exhaust gas purifying catalyst composition of the present invention.
  • a catalytically active component such as a metal, an alloy containing a noble metal element, a compound containing a noble metal element (e.g., an oxide of a noble metal element), and the like, in the exhaust gas purifying catalyst composition of the present invention.
  • the amount of the noble metal element in the exhaust gas purifying catalyst composition of the present invention is preferably 0.010% by mass based on the mass of the exhaust gas purifying catalyst composition of the present invention. 20 mass % or less, more preferably 0.050 mass % or more and 10 mass % or less, and still more preferably 0.10 mass % or more and 5.0 mass % or less.
  • the "amount of noble metal element” means the metal-equivalent amount of the one noble metal element when the catalyst composition contains one noble metal element, and the catalyst composition contains two or more noble metal elements. When the noble metal element is included, it means the sum of the metal conversion amounts of the two or more noble metal elements.
  • the amount of the noble metal element in the exhaust gas purifying catalyst composition of the present invention is obtained by analyzing a sample obtained from the exhaust gas purifying catalyst composition of the present invention with EDS or WDS (wavelength dispersive X-ray fluorescence spectrometer). It can be determined from direct elemental mapping and EDS elemental analysis of specified particles.
  • the noble metal element is preferably supported on Ce-based oxide particles and Ce--Zr-based composite oxide particles. At low to medium temperatures, the exhaust gas purification performance of the noble metal element supported on the Ce-based oxide particles is likely to be exhibited, and at high temperatures, the exhaust gas purification performance of the noble metal element supported on the Ce—Zr-based composite oxide particles is likely to be exhibited. . Therefore, since the noble metal element is supported on the Ce-based oxide particles and the Ce--Zr-based composite oxide particles, excellent exhaust gas purifying performance is exhibited in a wide temperature range. In particular, the exhaust gas purifying catalyst composition of the present invention exhibits excellent exhaust gas purifying performance at low to medium temperatures after being exposed to a high-temperature environment.
  • low temperature to medium temperature means a temperature of, for example, 50°C or higher and 400°C or lower, preferably 100°C or higher and 350°C or lower.
  • “Supported” means a state in which a catalytically active component such as a noble metal is physically or chemically adsorbed or held on the outer surface or inner surface of pores of Ce-based oxide particles and Ce—Zr-based mixed oxide particles. do.
  • a sample obtained from the exhaust gas purifying catalyst composition of the present invention is analyzed by SEM-EDX, and when the catalytically active component and Ce-based oxide particles are present in the same region, the catalytically active component is Ce-based It can be determined that they are supported on the oxide particles, and if the catalytically active component and the Ce—Zr-based composite oxide particles are present in the same region, the catalytically active component is the Ce—Zr-based composite oxide particles. It can be determined that the The amount of the noble metal element supported on the Ce-based oxide particles is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the mass of the Ce-based oxide particles. An upper limit is 20 mass %, for example.
  • the amount of the noble metal element supported on the Ce—Zr composite oxide particles is preferably 0.05% by mass or more, more preferably 0.10% by mass, based on the mass of the Ce—Zr composite oxide particles. That's it.
  • An upper limit is 20 mass %, for example.
  • the exhaust gas purifying catalyst composition of the present invention contains one or more inorganic oxide particles (hereinafter referred to as "other particles”) other than Ce-based oxide particles and Ce--Zr-based composite oxide particles. You can stay.
  • other particles means other particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified. (hereinafter referred to as “other particles as raw materials”).
  • Other particles are composed of oxides containing metal elements other than Ce and Zr.
  • examples of other particles include Al-based oxide particles, zirconia particles, silica particles, titania particles, and the like.
  • Al-based oxide particles generally have higher heat resistance than Ce-based oxide particles and Ce--Zr-based composite oxide particles. Therefore, the specific surface area of the exhaust gas purifying catalyst composition (especially the specific surface area after exposure to a high temperature environment) is improved, and the exhaust gas purifying performance of the exhaust gas purifying catalyst composition (especially after exposure to a high temperature environment exhaust gas purification performance) is improved.
  • the Al-based oxide particles are composed of Al-based oxides.
  • the Al-based oxide particles may or may not contain elements other than Al and O.
  • Elements other than Al and O include, for example, B, Si, rare earth elements (e.g., Y, Ce, La, Nd, Pr, Sm, Gd, etc.), Zr, Cr, alkaline earth metal elements (e.g., Mg, Ca , Sr, Ba, etc.), but it is preferable to select from Ce, La, Sr, Ba, etc. from the viewpoint of improving the heat resistance of the Al-based oxide.
  • rare earth elements e.g., Y, Ce, La, Nd, Pr, Sm, Gd, etc.
  • Zr, Cr alkaline earth metal elements
  • alkaline earth metal elements e.g., Mg, Ca , Sr, Ba, etc.
  • Al-based oxides examples include alumina particles (oxides consisting only of Al and O), oxides obtained by modifying the surface of alumina with elements other than Al and O, and elements other than Al and O in alumina. and oxides obtained by solid solution.
  • Specific examples of Al-based oxides containing elements other than Al and O include alumina-silica, alumina-silicate, alumina-zirconia, alumina-chromia, alumina-ceria, and alumina-lanthana.
  • elements other than Al and O may form a solid solution phase together with Al and O, or a single phase that is a crystalline phase or an amorphous phase (e.g., elements other than Al and O oxide phase), or both a solid solution phase and a single phase may be formed.
  • the Al 2 O 3 equivalent amount of Al in the Al-based oxide particles is based on the mass of the Al-based oxide particles. , preferably 70% by mass or more and 99.9% by mass or less, more preferably 80% by mass or more and 99.5% by mass or less, and still more preferably 90% by mass or more and 99% by mass or less.
  • the amount of the Al-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is preferably 10% by mass or more and 90% by mass or less, more preferably, based on the mass of the exhaust gas purifying catalyst composition of the present invention. 15% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 60% by mass or less.
  • the method for measuring the amount of Al-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention is the same as the method for measuring the amount of Ce-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention.
  • the catalyst composition for exhaust gas purification of the present invention contains Al-based oxide particles.
  • the ratio of the amount to the amount of the Ce-based oxide particles is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and still more preferably 0.3 or more and 3 or less, in mass ratio.
  • the average particle size of the Al-based oxide particles is preferably 1 ⁇ m or more and 50 ⁇ m or less, more preferably 2 ⁇ m or more and 30 ⁇ m or less. More preferably, it is 4 ⁇ m or more and 20 ⁇ m or less.
  • the method for measuring the average particle size of the Al-based oxide particles is the same as the method for measuring the average particle size of the Ce-based oxide particles.
  • the average particle size of the Al-based oxide particles can be adjusted in the same manner as the average particle size of the Ce-based oxide particles.
  • the average particle size of the Al-based oxide particles as the raw material is maintained, the average particle size of the Al-based oxide particles is usually the same as that of the raw material. It is the same as the average particle size of Al-based oxide particles.
  • Al-based oxide particles are distinguished from alumina used as a binder (hereinafter referred to as "alumina binder").
  • Alumina binder originates from the alumina sol used as a material of the catalyst composition.
  • the noble metal element When the exhaust gas purifying catalyst composition of the present invention contains other particles, the noble metal element may be supported on the other particles.
  • the meaning of "carrying" is the same as above. At high temperatures, the exhaust gas purifying performance of the noble metal elements supported on the other particles is likely to be exhibited. Therefore, by supporting the noble metal element on the Ce-based oxide particles, the Ce--Zr-based mixed oxide particles and other particles, the exhaust gas purification performance is improved in a wide temperature range.
  • the amount of the noble metal element carried on the other particles is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the mass of the other particles. In addition, an upper limit is 20 mass %, for example.
  • the exhaust gas purifying catalyst composition of the present invention may contain stabilizers, binders, and the like.
  • the binder include inorganic oxide binders such as alumina sol, zirconia sol, titania sol and silica sol.
  • stabilizers include nitrates, carbonates, oxides and sulfates of alkaline earth metal elements (eg, Sr, Ba, etc.).
  • the form of the exhaust gas purifying catalyst composition of the present invention is, for example, a powder, a compact, or a layer.
  • the exhaust gas purifying catalyst composition of the present invention comprises, for example, a noble metal salt-containing solution, Ce-based oxide particles as a raw material, Ce--Zr-based composite oxide particles as a raw material, and optionally other components (for example, it can be produced by mixing other particles, binders, stabilizers, etc. as raw materials, followed by drying and firing.
  • the fired product may be pulverized as necessary.
  • noble metal salts include nitrates, ammine complex salts, chlorides, and the like.
  • the solvent of the noble metal salt-containing solution is, for example, water (eg, ion-exchanged water, etc.).
  • the noble metal salt-containing solution may contain an organic solvent such as alcohol.
  • the drying temperature is, for example, 50° C. or higher and 150° C. or lower, and the drying time is, for example, 1 hour or longer and 3 hours or shorter.
  • the firing temperature is, for example, 300° C. or higher and 700° C. or lower, and the firing time is, for example, 1 hour or longer and 3 hours or shorter. Firing can be performed, for example, in an air atmosphere.
  • a heat load is applied to the Ce-based oxide particles as a raw material, and the crystallites of CeO 2 in the Ce-based oxide particles as a raw material It is preferable to adjust the diameter.
  • a heat load can be applied, for example, by firing at 1000° C. for 1 hour in an air atmosphere.
  • the crystallite size of CeO 2 in the Ce-based oxide particles as a raw material is preferably 7 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and still more preferably 30 nm or more.
  • the upper limit of the crystallite size of CeO 2 in the Ce-based oxide particles as a raw material is, for example, 200 nm, preferably 100 nm, more preferably 55 nm. Each of these upper limits may be combined with any of the above lower limits.
  • the method for measuring the crystallite size of CeO2 in Ce - based oxide particles as a raw material is the crystallite size of CeO2 in Ce - based oxide particles, except that the measurement is performed using the Ce-based oxide particles as a raw material. It is the same as the diameter measurement method.
  • the exhaust gas purifying catalyst of the present invention comprises a substrate and the catalyst layer of the present invention provided on the substrate.
  • the exhaust gas purifying catalyst of the present invention may have a catalyst layer other than the catalyst layer of the present invention at one or more positions selected from the lower side, the upper side, the downstream side, and the upstream side of the catalyst layer of the present invention. .
  • the base material can be appropriately selected from base materials generally used as base materials for exhaust gas purification catalysts.
  • substrates include wall-flow type substrates and flow-through type substrates.
  • the material that constitutes the base material can be appropriately selected from materials that are generally used as base materials for exhaust gas purification catalysts.
  • the material constituting the base material is preferably a material that can stably maintain the shape of the base material even when the base material is exposed to exhaust gas of 400° C. or higher, for example.
  • Materials for the substrate include, for example, cordierite, silicon carbide (SiC), ceramics such as aluminum titanate, and alloys such as stainless steel.
  • the catalyst layer of the present invention is composed of the exhaust gas purifying catalyst composition of the present invention. That is, the catalyst layer of the present invention contains Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element.
  • the catalyst layer of the present invention contains Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element.
  • the explanations in the above sections of ⁇ Ce-based oxide particles>, ⁇ Ce--Zr-based mixed oxide particles>, ⁇ Noble metal element> and ⁇ Other components> also apply to the catalyst layer of the present invention.
  • the exhaust gas purifying catalyst composition of the present invention is read as "the catalyst layer of the present invention".
  • the mass of the catalyst layer of the present invention per unit volume of the substrate is preferably 10 g/L or more and 300 g/L or less, more preferably. is 30 g/L or more and 200 g/L or less, more preferably 50 g/L or more and 150 g/L or less.
  • an exhaust gas purifying catalyst 1A is arranged in an exhaust passage within an exhaust pipe P of an internal combustion engine.
  • the internal combustion engine is, for example, a gasoline engine or the like.
  • Exhaust gas discharged from the internal combustion engine flows through an exhaust passage in the exhaust pipe P from one end to the other end of the exhaust pipe P, and is purified by the exhaust gas purification catalyst 1A provided in the exhaust pipe P.
  • the exhaust gas flow direction is indicated by X.
  • the upstream side in the exhaust gas flow direction X may be referred to as the "exhaust gas inflow side”
  • the downstream side in the exhaust gas flow direction X may be referred to as the "exhaust gas outflow side”.
  • exhaust gas purifying catalyst 1A In addition to the exhaust gas purifying catalyst 1A, other exhaust gas purifying catalysts may be arranged in the exhaust passage in the exhaust pipe P.
  • the exhaust gas purifying catalyst 1A may be arranged on the upstream side of the exhaust passage in the exhaust pipe P, and another exhaust gas purifying catalyst may be arranged on the downstream side of the exhaust passage in the exhaust pipe P.
  • Other exhaust gas purifying catalysts include, for example, an exhaust gas purifying catalyst 1B, which will be described later.
  • the exhaust gas purifying catalyst 1A includes a substrate 10 and a catalyst layer 20 provided on the substrate 10. As shown in FIGS. 2 to 4, the exhaust gas purifying catalyst 1A includes a substrate 10 and a catalyst layer 20 provided on the substrate 10. As shown in FIGS. 2 to 4, the exhaust gas purifying catalyst 1A includes a substrate 10 and a catalyst layer 20 provided on the substrate 10. As shown in FIGS. 2 to 4, the exhaust gas purifying catalyst 1A includes a substrate 10 and a catalyst layer 20 provided on the substrate 10. As shown in FIGS.
  • the catalyst layer 20 is composed of the exhaust gas purifying catalyst composition of the present invention. That is, the catalyst layer 20 contains Ce-based oxide particles, Ce--Zr-based composite oxide particles, and noble metal elements.
  • the above description of the catalyst layer of the present invention also applies to catalyst layer 20 .
  • the substrate 10 includes a tubular portion 11 that defines the outer shape of the substrate 10, partition walls 12 provided in the tubular portion 11, and cells partitioned by the partition walls 12. 13.
  • the tubular portion 11 has a cylindrical shape, but may have other shapes such as an elliptical tubular shape and a polygonal tubular shape.
  • partition walls 12 exist between adjacent cells 13, and the adjacent cells 13 are partitioned by the partition walls 12.
  • the partition wall 12 is preferably porous.
  • the thickness of the partition 12 is, for example, 20 ⁇ m or more and 1500 ⁇ m or less.
  • the cell 13 extends in the exhaust gas flow direction X and has an exhaust gas inflow side end and an exhaust gas outflow side end.
  • both the end on the exhaust gas inflow side and the exhaust gas outflow side of the cell 13 are open. Therefore, the exhaust gas that has flowed in from the end (opening) of the cell 13 on the exhaust gas inflow side flows out from the end (opening) of the cell 13 on the exhaust gas outflow side.
  • Such a mode is called a flow-through type.
  • the planar view shape of the end (opening) of the cell 13 on the exhaust gas inflow side is quadrangular, but it may be hexagonal, octagonal, or other shape.
  • the planar view shape of the end (opening) of the cell 13 on the exhaust gas outflow side is the same.
  • the cell density per square inch of the substrate 10 is, for example, 300 cells or more and 900 cells or less.
  • the cell density per square inch of the base material 10 is the total number of cells 13 per square inch in a cross section obtained by cutting the base material 10 along a plane perpendicular to the flow direction X of the exhaust gas.
  • the catalyst layer 20 is provided on the partition wall portion 12 of the substrate 10 .
  • the catalyst layer 20 extends along the exhaust gas flow direction X from the exhaust gas inflow side end of the partition wall 12 to the exhaust gas outflow side end of the partition wall 12 .
  • the catalyst layer 20 may extend along the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas inflow side so as not to reach the end of the partition wall 12 on the exhaust gas outflow side. It may extend from the end of the partition wall 12 on the exhaust gas outflow side along the direction opposite to the exhaust gas flow direction X so as not to reach the exhaust gas inflow side end of the partition wall portion 12 .
  • the exhaust gas purifying catalyst 1A can be manufactured by forming the catalyst layer 20 on the partition wall portion 12 of the substrate 10 .
  • a noble metal salt-containing solution, Ce-based oxide particles as raw materials, Ce—Zr-based composite oxide particles as raw materials, and optionally other components (for example, other particles as raw materials, binders, Stabilizer, etc.) is mixed to prepare a slurry, the slurry is applied on the partition wall portion 12 of the substrate 10, dried, and fired to form the catalyst layer 20 on the partition wall portion 12 of the substrate 10. can do.
  • the noble metal salt, the solvent of the noble metal salt-containing solution, the drying conditions, the calcining conditions, the crystallite size of CeO2 in the Ce - based oxide particles as the raw material, etc. are the same as in the method for producing the exhaust gas purifying catalyst composition of the present invention. .
  • the exhaust gas purifying catalyst 1B is In the base material 10, a first sealing portion 14 that seals the ends of some of the cells 13 on the exhaust gas outflow side, and a second sealing portion that seals the ends of the remaining cells 13 on the exhaust gas inflow side.
  • the inflow-side cell 13a is open at the end on the exhaust gas inflow side and the end on the exhaust gas outflow side is closed with the first sealing portion 14 in the base material 10; And, the end on the exhaust gas inflow side is closed by the second sealing portion 15, and the outflow side cell 13b is formed in which the end on the exhaust gas outflow side is open;
  • the catalyst layer 20a is provided on the inflow side cell 13a side of the partition wall portion 12 of the base material 10
  • the catalyst layer 20b is provided on the outflow side cell 13b side of the partition wall portion 12 of the base material 10. It is different from the catalyst for catalyst 1A.
  • a plurality of (for example, four) outflow-side cells 13b are arranged adjacently around one inflow-side cell 13a.
  • the outflow side cell 13b adjacent to 13a is separated by a porous partition wall portion 12 .
  • the catalyst layer 20a extends along the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas inflow side so as not to reach the exhaust gas outflow end of the partition wall 12. there is The catalyst layer 20 a may extend from the end of the partition wall 12 on the exhaust gas inflow side to the end of the partition wall 12 on the exhaust gas outflow side.
  • the catalyst layer 20b is formed along the direction opposite to the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas outflow side so as not to reach the end of the partition wall 12 on the exhaust gas inflow side. extended.
  • the catalyst layer 20b may extend from the end of the partition wall 12 on the exhaust gas outflow side to the end of the partition wall 12 on the exhaust gas inflow side.
  • At least one of the catalyst layers 20a and 20b is the catalyst layer of the present invention containing Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element, and the above description of the catalyst layer of the present invention applies. be done.
  • the composition and the like of the catalyst layers 20a and 20b may be the same or different.
  • the exhaust gas that has flowed in from the end (opening) of the inflow-side cell 13a on the exhaust gas inflow side passes through the porous partition wall portion 12 and reaches the end (opening) of the outflow-side cell 13b on the exhaust gas outflow side. opening).
  • a mode is called a wall-flow type.
  • the exhaust gas purifying catalyst 1B when the exhaust gas that has flowed in from the exhaust gas inflow side end (opening) of the inflow-side cell 13a passes through the porous partition wall portion 12, particulate matter (PM) in the exhaust gas ) are collected in the pores of the partition wall portion 12 . Therefore, the exhaust gas purifying catalyst 1B is useful as a particulate filter for gasoline engines or a diesel particulate filter for diesel engines.
  • the exhaust gas purifying catalyst 1B can be manufactured by the following method.
  • the end of the substrate 10 on the exhaust gas inflow side is immersed in the slurry for forming the catalyst layer 20a, and the slurry is sucked from the opposite side and dried to form a precursor layer of the catalyst layer 20a.
  • the end of the substrate 10 on the exhaust gas outflow side is immersed in the slurry for forming the catalyst layer 20b, and the slurry is sucked from the opposite side and dried to form a precursor layer of the catalyst layer 20b.
  • After forming a precursor layer of the catalyst layer 20a and a precursor layer of the catalyst layer 20b they are fired to form the catalyst layer 20a and the catalyst layer 20b, thereby manufacturing the exhaust gas purifying catalyst 1B.
  • the manufacturing conditions and the like of the exhaust gas purifying catalyst 1B are the same as those of the exhaust gas purifying catalyst 1A.
  • a cerium oxide powder was prepared and used in the following examples, comparative examples and comparative examples.
  • the CeO2 equivalent amount of Ce in the cerium oxide powder was nearly 100 wt% (>99 wt%).
  • Example 1 (1) Preparation of Ce - based oxide Cerium oxide powder (CeO2 equivalent amount: 95.0 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 5.0 g), and the mixture was left at room temperature for 2 hours. After stirring, it was evaporated to dryness to obtain a dry powder. The resulting dry powder was calcined in the air at 1000° C. for 1 hour, and the Ce-based oxide powder of Example 1 (amount of Ce converted to CeO2 : 95.0% by mass , amount of Al converted to Al2O3 : 5.0% by mass) was obtained. 0% by mass) was obtained.
  • Electron probe microanalyzer (EPMA) analysis of the resulting catalyst composition detected Al 2 O 3 co-located with CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Al.
  • Example 2 Preparation of Ce-based oxide Ce of Example 2 was prepared in the same manner as in Example 1, except that an aqueous magnesium nitrate solution (Mg in terms of MgO: 5.0 g) was used instead of the aqueous aluminum nitrate solution. A system oxide powder ( amount of Ce converted to CeO2: 95.0% by mass, amount of Mg converted to MgO: 5.0% by mass) was obtained.
  • Mg in terms of MgO 5.0 g
  • a system oxide powder amount of Ce converted to CeO2: 95.0% by mass, amount of Mg converted to MgO: 5.0% by mass
  • Example 3 (1) Preparation of Ce-based Oxide In the same manner as in Example 1, except that an aqueous lanthanum nitrate solution (La converted to La 2 O 3 : 5.0 g) was used instead of the aqueous aluminum nitrate solution. 3 (amount of Ce converted to CeO2: 95.0% by mass , amount of La converted to La2O3 : 5.0% by mass).
  • Example 4 (1) Preparation of Ce-based Oxide The procedure of Example 1 was repeated except that an aqueous solution of praseodymium nitrate (5.0 g of Pr in terms of Pr 6 O 11 ) was used instead of the aqueous solution of aluminum nitrate. 4 (amount of Ce converted to CeO2: 95.0% by mass, amount of Pr converted to Pr6O11 : 5.0% by mass).
  • Example 5 (1) Production of Ce-based Oxide The procedure of Example 1 was repeated except that an aqueous solution of yttrium nitrate (Y 2 O 3 equivalent: 5.0 g) was used instead of the aqueous solution of aluminum nitrate. A Ce - based oxide powder No. 5 (amount of Ce converted to CeO2: 95.0% by mass, amount of Y converted to Y2O3: 5.0% by mass) was obtained.
  • Example 6 (1) Preparation of Ce-based oxide The procedure of Example 1 was repeated except that an aqueous solution of neodymium nitrate (Nd converted to Nd 2 O 3 : 5.0 g) was used instead of the aqueous solution of aluminum nitrate. No. 6 Ce - based oxide powder (amount of Ce converted to CeO2: 95.0% by mass , amount of Nd converted to Nd2O3 : 5.0% by mass) was obtained.
  • Zr in terms of ZrO 2 50% by mass
  • La in terms of La 2 O 3 10% by mass
  • Al-based oxide powder Al in terms of Al 2 O 3 : 99% by mass
  • La converted amount of La 2 O 3 1% by mass
  • 33.0 parts by mass were sequentially added and allowed to stand for 1 hour to form a dinitrodiammineplatinum nitric acid aqueous solution into a Ce—Zr-based composite oxide powder and an Al-based oxide powder.
  • the obtained dry powder was calcined at 500° C. for 1 hour in an air atmosphere to obtain a powdery catalyst composition.
  • Zr converted to ZrO2 50% by mass
  • La converted to La2O3 10 % by mass
  • Al - based oxide powder Al converted to Al2O3 : 99% by mass
  • 28.0 parts by mass of La equivalent to La 2 O 3 1% by mass
  • cerium oxide powder CeO 2 equivalent amount of Ce: approximately 100% by mass (>99% by mass)
  • the obtained dry powder was calcined at 500° C. for 1 hour in an air atmosphere to obtain a powdery catalyst composition.
  • Comparative Example 5 (1) Preparation of Ce-based oxide Ce of Comparative Example 5 was prepared in the same manner as in Example 1, except that an aqueous tin nitrate solution (Sn converted to SnO: 5.0 g) was used instead of the aqueous aluminum nitrate solution. A system oxide powder ( amount of Ce converted to CeO2: 95.0% by mass, amount of Sn converted to SnO: 5.0% by mass) was obtained.
  • Comparative Example 6 (1) Preparation of Ce-based oxide A comparative example was prepared in the same manner as in Example 1, except that an aqueous indium nitrate solution ( in terms of In2O3 of In : 5.0 g) was used instead of the aqueous aluminum nitrate solution. 6 (amount of Ce converted to CeO2: 95.0% by mass , amount of In converted to In2O3: 5.0% by mass).
  • the number B of noble metal atoms exposed on the noble metal particle surface is the amount of CO adsorption measured by the CO pulse method, based on the premise that the noble metal atoms exposed on the noble metal particle surface and CO adsorb at a ratio of 1:1. calculated from
  • the temperature of the catalyst composition was raised to 800°C under the flow of He, and the temperature was lowered to 300°C after a pretreatment of holding at that temperature for 40 minutes. Then, while the catalyst composition was kept at 300 ° C., O gas was injected in 4 pulses and subjected to oxidation treatment, and then a test gas containing CO was injected in 10 pulses and consumed.
  • 0.1 g of the catalyst composition after heat treatment was filled in a reaction tube, and simulated exhaust gas (CO: 3000 ppm, C 3 H 6 : 1000 ppmC, NO: 500 ppm, O 2 : 0.28%, CO 2 : 14%, H 2 O: 10%, N 2 : balance) into the reaction tube under the conditions of a temperature increase rate of 10°C/min, an air-fuel ratio (A/F) of 14.6, and a total flow rate of 1000 mL/min. introduced.
  • A/F is an abbreviation for Air/Fuel, and is a numerical value indicating the ratio of air to fuel. After the temperature was raised to 600° C.
  • the gas temperature at the inlet of the reaction tube when the NO purification rate reached 50% was obtained as the light-off temperature T50 (°C). Note that the light-off temperature T50 was obtained when the temperature was raised.
  • Table 1 shows the average particle size of the Ce-based oxide powder and the crystallite size of CeO 2 measured using the Ce-based oxide powder.
  • Table 2 shows the measurement results of CeO 2 crystallite size, noble metal dispersity, OSC content and T50 measured using the catalyst composition.
  • Table 1 also shows the composition and addition amount of the Ce-based oxide powder used as the material of the catalyst composition in Examples 1-6 and Comparative Examples 1-6.
  • CeO 2 is the amount of Ce converted to CeO 2 (% by mass)
  • Al 2 O 3 is the amount of Al converted to Al 2 O 3 (% by mass)
  • MgO is the amount of Mg converted to MgO.
  • the T50 of the catalyst compositions of Examples 1-6 is lower than the T50 of the catalyst compositions of Comparative Examples 1-6, and the exhaust gas purification performance of the catalyst compositions of Examples 1-6 was better than the exhaust gas purification performance of the catalyst compositions of Comparative Examples 1-6.
  • the noble metal dispersities of the catalyst compositions of Examples 1 and 2 are higher than the noble metal dispersities of the catalyst compositions of Examples 3-6, while the catalyst compositions of Examples 3-6
  • the amount of OSC was greater than that of the catalyst compositions of Examples 1 and 2. From these results, it was found that the catalyst compositions of Examples 1 and 2 and the catalyst compositions of Examples 3 to 6 have different mechanisms for improving exhaust gas purification performance.
  • the Ce-based oxide particles contain the first additional element selected from Al and Mg
  • the heat resistance of the Ce-based oxide particles is improved, the specific surface area of the Ce-based oxide particles is reduced, and the resulting Ce-based
  • the burial of the catalytically active component in the oxide particles is suppressed, thereby improving the specific surface area of the exhaust gas purifying catalyst composition and improving the degree of dispersion of the catalytically active component, thereby improving the exhaust gas purification performance of the exhaust gas purifying catalyst composition. is expected to improve.
  • the Ce-based oxide powder contains a second additional element selected from La, Pr, Y and Nd
  • the oxygen storage capacity of the Ce-based oxide particles after supporting the noble metal element is improved, thereby purifying the exhaust gas. This is thought to improve the ability of the catalyst composition for exhaust gas purification.
  • Test Example 2 In Test Example 2, a test was conducted to determine a suitable range for the content of the first additional element selected from Al and Mg.
  • Test Example 2A Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 99.9 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 0.1 g). A 2A Ce-based oxide powder (amount of Ce converted to CeO2 : 99.9% by mass , amount of Al converted to Al2O3 : 0.1% by mass) was obtained.
  • Test Example 2B Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 97.5 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 2.5 g). A Ce-based oxide powder of 2B (amount of Ce converted to CeO2: 97.5% by mass , amount of Al converted to Al2O3 : 2.5 % by mass) was obtained.
  • Test Example 2C The Ce-based oxide powder obtained in Example 1 (amount of Ce in terms of CeO 2 : 95.0% by mass, amount of Al in terms of Al 2 O 3 : 5.0% by mass) was subjected to the Ce-based oxidation of Test Example 2C. It was made into a powder.
  • Test Example 2D Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 90.0 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 10.0 g). A 2D Ce-based oxide powder (amount of Ce converted to CeO2: 90.0% by mass , amount of Al converted to Al2O3 : 10.0% by mass) was obtained.
  • Test Example 2E Test Example _ A 2E Ce-based oxide powder (amount of Ce converted to CeO2 : 80.0% by mass , amount of Al converted to Al2O3 : 20.0% by mass) was obtained.
  • Test Example 2F The cerium oxide powder was sintered in the atmosphere at 1000° C. for 1 hour to obtain a Ce-based oxide powder (amount of Ce converted to CeO 2 : approximately 100% by mass (>99% by mass)) of Test Example 2F.
  • the BET specific surface areas of the Ce-based oxide powders of Test Examples 2A to 2E were larger than the BET specific surface areas of the Ce-based oxide powder of Test Example 2F. From these results, the preferable range of the oxide conversion amount of the first additional element in the Ce-based oxide powder is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide powder. There was found.
  • Test Example 3 In Test Example 3, a test was conducted to determine a suitable range for the content of the second additional element selected from La, Pr, Y and Nd.
  • Test Example 3A Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( Ce in terms of CeO2: 99.9 g) was added to an aqueous lanthanum nitrate solution (La in terms of La 2 O 3 : 0.1 g). A 3A Ce - based oxide powder (amount of Ce converted to CeO2: 99.9% by mass , amount of La converted to La2O3: 0.1% by mass) was obtained.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3A was used instead of the Ce-based oxide powder of Example 1.
  • Test Example 3B Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( Ce in terms of CeO2: 97.5 g) was added to an aqueous lanthanum nitrate solution (La in terms of La 2 O 3 : 2.5 g). A 3B Ce - based oxide powder (amount of Ce converted to CeO2: 97.5% by mass, amount of La converted to La2O3: 2.5 % by mass) was obtained.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3B was used instead of the Ce-based oxide powder of Example 1.
  • Test Example 3C The Ce-based oxide powder obtained in Example 3 (amount of Ce in terms of CeO2: 95.0% by mass, amount of La in terms of La2O3: 5.0% by mass) was subjected to the Ce - based oxidation of Test Example 3C . It was made into a powder.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3C was used instead of the Ce-based oxide powder of Example 1.
  • Example 3D Test Example was carried out in the same manner as in Example 1 , except that cerium oxide powder ( CeO2 equivalent amount: 90.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 10.0 g). A 3D Ce - based oxide powder (amount of Ce converted to CeO2: 90.0% by mass, amount of La converted to La2O3: 10.0% by mass) was obtained.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3D was used instead of the Ce-based oxide powder of Example 1.
  • Test Example 3E Test Example was carried out in the same manner as in Example 1 , except that cerium oxide powder ( CeO2 equivalent amount: 80.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 20.0 g). A 3E Ce - based oxide powder (amount of Ce converted to CeO2: 80.0% by mass , amount of La converted to La2O3: 20.0% by mass) was obtained.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3E was used instead of the Ce-based oxide powder of Example 1.
  • Test Example 3F The cerium oxide powder was sintered in the atmosphere at 1000° C. for 1 hour to obtain a Ce-based oxide powder (amount of Ce converted to CeO 2 : approximately 100% by mass (>99% by mass)) of Test Example 3F.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3F was used instead of the Ce-based oxide powder of Example 1.
  • Test Example 3G Test Example was carried out in the same manner as in Example 1 except that cerium oxide powder ( CeO2 equivalent amount: 70.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 30.0 g). A 3G Ce - based oxide powder (amount of Ce converted to CeO2: 70.0% by mass, amount of La converted to La2O3: 30.0% by mass) was obtained.
  • a powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3G was used instead of the Ce-based oxide powder of Example 1.
  • the OSC amounts of the catalyst compositions of Test Examples 3A to 3E were greater than the OSC amounts of the catalyst compositions of Test Examples 3F and 3G. From these results, the preferable range of the oxide conversion amount of the second additional element in the Ce-based oxide powder is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide powder. There was found.

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Abstract

The purpose of the present invention is to provide a catalyst composition for exhaust gas purification and a catalyst for exhaust gas purification, which both have improved exhaust gas purification capability. The catalyst composition for exhaust gas purification contains Ce-based oxide particles, Ce-Zr-based complex oxide particles, and a noble metal element. The Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y, and Nd. The amount of the at least one additional element, as expressed in terms of oxides, in the Ce-based oxide particles is 0.1-20 mass% with respect to the mass of the Ce-based oxide particles.

Description

排ガス浄化用触媒組成物及び排ガス浄化用触媒Exhaust gas purifying catalyst composition and exhaust gas purifying catalyst
　本発明は、排ガス浄化用触媒組成物及び排ガス浄化用触媒に関する。 The present invention relates to an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst.
　自動車、バイク等の内燃機関から排出される排ガス中には、炭化水素（ＴＨＣ）、一酸化炭素（ＣＯ）、窒素酸化物（ＮＯｘ）等の有害成分が含まれている。これらの有害成分を浄化して無害化する排ガス浄化用触媒として、ＴＨＣを酸化して水及び二酸化炭素に、ＣＯを酸化して二酸化炭素に、ＮＯｘを還元して窒素に変換する触媒活性を有する三元触媒が使用されている。 Exhaust gases emitted from internal combustion engines such as automobiles and motorcycles contain harmful components such as hydrocarbons (THC), carbon monoxide (CO), and nitrogen oxides (NOx). As an exhaust gas purifying catalyst that purifies and detoxifies these harmful components, it has a catalytic activity that oxidizes THC to water and carbon dioxide, oxidizes CO to carbon dioxide, and reduces NOx to nitrogen. A three-way catalyst is used.
　三元触媒等の排ガス浄化用触媒では、触媒活性成分（例えば、Ｐｔ、Ｐｄ、Ｒｈ等の貴金属粒子）を担持する担体として、アルミナ（Ａｌ２Ｏ３）等のＡｌ系酸化物、Ｃｅ－Ｚｒ系複合酸化物等が使用されている（例えば、特許文献１及び２）。なお、本明細書において、「Ａｌ系酸化物」は、Ａｌを含む酸化物であって、ＡｌのＡｌ２Ｏ３換算量が酸化物の質量を基準として７０質量％以上である酸化物を意味し、「Ｃｅ－Ｚｒ系複合酸化物」は、Ｃｅ及びＺｒを含む複合酸化物であって、ＣｅのＣｅＯ２換算量が複合酸化物の質量を基準として５質量％以上９０質量％以下である複合酸化物を意味する。 In exhaust gas purifying catalysts such as three-way catalysts, Al-based oxides such as alumina (Al 2 O 3 ), Ce—Zr system composite oxides and the like are used (for example, Patent Documents 1 and 2). In the present specification, "Al-based oxide" means an oxide containing Al, and the amount of Al converted to Al 2 O 3 is 70% by mass or more based on the mass of the oxide. "Ce-Zr-based composite oxide" is a composite oxide containing Ce and Zr, and the amount of Ce converted to CeO2 is 5 mass% or more and 90 mass% or less based on the mass of the composite oxide. means a composite oxide.
　Ｃｅ－Ｚｒ系複合酸化物は、酸素貯蔵能（ＯＳＣ：Ｏｘｙｇｅｎ　Ｓｔｏｒａｇｅ　Ｃａｐａｃｉｔｙ）を有する材料（ＯＳＣ材）であり、排ガス中の酸素濃度の変動を緩和して触媒の作動ウインドウを拡大する。ＯＳＣ材としては、その他に、酸化セリウム（ＣｅＯ２）等のＣｅ系酸化物が使用されている（例えば、特許文献２）。但し、ＣｅＯ２は、酸素貯蔵能が低いため、一般的には、三元触媒の触媒活性成分を担持する担体としては使用されていない。なお、本明細書において、「Ｃｅ系酸化物」は、Ｃｅを含む酸化物であって、ＣｅのＣｅＯ２換算量が酸化物の質量を基準として８０質量％以上である酸化物を意味する。 A Ce—Zr-based composite oxide is a material (OSC material) having an oxygen storage capacity (OSC), and mitigates fluctuations in the oxygen concentration in the exhaust gas to expand the operating window of the catalyst. Ce-based oxides such as cerium oxide (CeO 2 ) are also used as OSC materials (for example, Patent Document 2). However, since CeO 2 has a low oxygen storage capacity, it is generally not used as a carrier for supporting catalytically active components of a three-way catalyst. In this specification, the term "Ce-based oxide" means an oxide containing Ce and having a CeO2 equivalent amount of Ce of 80% by mass or more based on the mass of the oxide.
特開２０１７－０３９０６９号公報JP 2017-039069 A 特開２００６－２９７３７２号公報JP 2006-297372 A
　Ｃｅ系酸化物は、触媒活性成分（例えば、Ｐｔ、Ｐｄ、Ｒｈ等の貴金属粒子）に対する親和性は高いが、耐熱性は低い。一方、Ｃｅ－Ｚｒ系複合酸化物は、耐熱性は高いが、触媒活性成分（例えば、Ｐｔ、Ｐｄ、Ｒｈ等の貴金属粒子）に対する親和性は比較的低い。したがって、触媒活性成分を担持する担体としてＣｅ系酸化物及びＣｅ－Ｚｒ系複合酸化物を併用することにより、一方の弱点を他方で補うことができる。しかしながら、Ｃｅ系酸化物及びＣｅ－Ｚｒ系複合酸化物を併用しても、排ガス浄化性能が低下する場合がある。 Ce-based oxides have a high affinity for catalytically active components (for example, precious metal particles such as Pt, Pd, and Rh), but have low heat resistance. On the other hand, Ce—Zr-based composite oxides have high heat resistance, but relatively low affinity for catalytically active components (for example, particles of noble metals such as Pt, Pd, and Rh). Therefore, by using both a Ce-based oxide and a Ce--Zr-based composite oxide as a carrier for supporting a catalytically active component, the weak points of one can be compensated for by the other. However, even if a Ce-based oxide and a Ce--Zr-based composite oxide are used in combination, the exhaust gas purification performance may be lowered.
　例えば、触媒活性成分を担持する担体としてＣｅＯ２を使用する場合、ＣｅＯ２の耐熱性が低いことに起因して、ＣｅＯ２同士の凝集、ＣｅＯ２の小細孔の消失（すなわち比表面積の低下）等が生じ、それらに伴って触媒活性成分の埋没が引き起こされ、排ガス浄化性能が低下する場合がある。ＣｅＯ２同士の凝集及びＣｅＯ２の比表面積の低下は、高温環境下で生じやすいため、排ガス浄化性能の低下は、高温環境に曝露された後に生じやすい。なお、本明細書において、「高温」は、例えば８００℃以上、特に９００℃以上の温度を意味する。 For example, when CeO2 is used as a support for supporting a catalytically active component, due to the low heat resistance of CeO2, CeO2 aggregates with each other, disappearance of small pores in CeO2 ( i.e., decrease in specific surface area ), etc., may occur, which may lead to the burial of the catalytically active component, thereby degrading the exhaust gas purification performance. Aggregation of CeO 2 and reduction in the specific surface area of CeO 2 are likely to occur in a high temperature environment, and thus deterioration in exhaust gas purification performance is likely to occur after exposure to a high temperature environment. In this specification, "high temperature" means a temperature of, for example, 800°C or higher, particularly 900°C or higher.
　また、触媒活性成分を担持する担体としてＣｅＯ２を使用する場合、ＣｅＯ２の酸素貯蔵能が低いことに起因して、排ガス浄化性能が低下する場合がある。 In addition, when CeO 2 is used as a carrier for supporting catalytically active components, the exhaust gas purification performance may decrease due to the low oxygen storage capacity of CeO 2 .
　そこで、本発明は、Ｃｅ系酸化物及びＣｅ－Ｚｒ系複合酸化物を利用した排ガス浄化用触媒組成物及び排ガス浄化用触媒であって、排ガス浄化性能（特に、高温環境に曝露された後の排ガス浄化性能）が向上した排ガス浄化用触媒組成物及び排ガス浄化用触媒を提供することを目的とする。 Therefore, the present invention provides an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst using a Ce-based oxide and a Ce—Zr-based composite oxide, which have exhaust gas purifying performance (especially after being exposed to a high-temperature environment An object of the present invention is to provide an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst with improved exhaust gas purifying performance.
　本発明者らは、Ｃｅ系酸化物及びＣｅ－Ｚｒ系複合酸化物を利用した排ガス浄化用触媒組成物及び排ガス浄化用触媒において、Ｃｅ系酸化物にＡｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素を添加することにより、排ガス浄化性能（特に、高温環境に曝露された後の排ガス浄化性能）が向上することを見出した。 The present inventors have found that in a catalyst composition for purifying an exhaust gas and a catalyst for purifying an exhaust gas using a Ce-based oxide and a Ce—Zr-based composite oxide, Al, Mg, La, Pr, Y and Nd are added to the Ce-based oxide. It has been found that the addition of at least one additional element selected from is improved in exhaust gas purification performance, especially after exposure to a high temperature environment.
　本発明は、上記知見に基づいて完成された発明であり、以下の発明を包含する。 The present invention is an invention completed based on the above findings, and includes the following inventions.
［１］Ｃｅ系酸化物粒子と、Ｃｅ－Ｚｒ系複合酸化物粒子と、貴金属元素とを含む排ガス浄化用触媒組成物であって、
　前記Ｃｅ系酸化物粒子が、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素を含み、
　前記Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量が、前記Ｃｅ系酸化物粒子の質量を基準として、８０質量％以上であり、
　前記Ｃｅ系酸化物粒子における前記少なくとも１種の追加元素の酸化物換算量が、前記Ｃｅ系酸化物粒子の質量を基準として、０．１質量％以上２０質量％以下であり、
　前記Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算量が、前記Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、５質量％以上９０質量％以下である、排ガス浄化用触媒組成物。
［２］基材と、前記基材に設けられた触媒層とを備える排ガス浄化用触媒であって、
　前記触媒層が、［１］に記載の排ガス浄化用触媒組成物で構成されている、排ガス浄化用触媒。 [1] An exhaust gas purifying catalyst composition containing Ce-based oxide particles, Ce--Zr-based mixed oxide particles, and a noble metal element,
The Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y and Nd,
The CeO 2 equivalent amount of Ce in the Ce-based oxide particles is 80% by mass or more based on the mass of the Ce-based oxide particles,
The amount of the at least one additional element in the Ce-based oxide particles in terms of oxide is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide particles,
A catalyst composition for exhaust gas purification, wherein the CeO 2 equivalent amount of Ce in the Ce—Zr-based mixed oxide particles is 5% by mass or more and 90% by mass or less based on the mass of the Ce—Zr-based mixed oxide particles. .
[2] An exhaust gas purification catalyst comprising a substrate and a catalyst layer provided on the substrate,
An exhaust gas purifying catalyst, wherein the catalyst layer is composed of the exhaust gas purifying catalyst composition according to [1].
　本発明により、Ｃｅ系酸化物及びＣｅ－Ｚｒ系複合酸化物を利用した排ガス浄化用触媒組成物及び排ガス浄化用触媒であって、排ガス浄化性能（特に、高温環境に曝露された後の排ガス浄化性能）が向上した排ガス浄化用触媒組成物及び排ガス浄化用触媒が提供される。 According to the present invention, an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst using a Ce-based oxide and a Ce—Zr-based composite oxide, which have an exhaust gas purifying performance (in particular, exhaust gas purifying after exposure to a high temperature environment Provided are an exhaust gas purifying catalyst composition and an exhaust gas purifying catalyst with improved performance.
図１は、本発明の第１実施形態に係る排ガス浄化用触媒が内燃機関の排気通路に配置されている状態を示す一部端面図である。FIG. 1 is a partial end view showing a state in which an exhaust gas purifying catalyst according to a first embodiment of the present invention is arranged in an exhaust passage of an internal combustion engine. 図２は、図１のＡ－Ａ線端面図である。FIG. 2 is an end view taken along the line AA of FIG. 1. FIG. 図３は、図２中の符号Ｒで示す領域の拡大図である。FIG. 3 is an enlarged view of the area indicated by symbol R in FIG. 図４は、図１のＢ－Ｂ線端面図である。4 is an end view taken along the line BB of FIG. 1. FIG. 図５は、本発明の第２実施形態に係る排ガス浄化用触媒の端面図（図４に対応する端面図）である。FIG. 5 is an end view (end view corresponding to FIG. 4) of the exhaust gas purifying catalyst according to the second embodiment of the present invention.
≪排ガス浄化用触媒組成物≫
　以下、本発明の排ガス浄化用触媒組成物について説明する。 ≪Catalyst composition for purification of exhaust gas≫
The exhaust gas purifying catalyst composition of the present invention will be described below.
＜Ｃｅ系酸化物粒子＞
　本発明の排ガス浄化用触媒組成物は、Ｃｅ系酸化物粒子を含む。なお、本明細書において、「Ｃｅ系酸化物粒子」は、別段規定される場合を除き、本発明の排ガス浄化用触媒組成物に含まれるＣｅ系酸化物粒子を意味し、本発明の排ガス浄化用触媒組成物の原料として使用されるＣｅ系酸化物粒子（以下「原料としてのＣｅ系酸化物粒子」という。）と区別される。 <Ce-based oxide particles>
The exhaust gas purifying catalyst composition of the present invention contains Ce-based oxide particles. In this specification, the term "Ce-based oxide particles" means Ce-based oxide particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified. It is distinguished from the Ce-based oxide particles used as a raw material of the catalyst composition for industrial use (hereinafter referred to as "Ce-based oxide particles as a raw material").
　Ｃｅ系酸化物粒子は、Ｃｅ系酸化物で構成されている。Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは８０質量％以上、より好ましくは８５質量％以上、より一層好ましくは９０質量％以上である。これにより、触媒活性成分に対するＣｅ系酸化物粒子の親和性が向上し、Ｃｅ系酸化物粒子に担持された触媒活性成分同士のシンタリングの発生が抑制される。したがって、触媒活性成分の分散度が向上し、排ガス浄化用触媒組成物の排ガス浄化性能が向上する。かかる効果は、高温環境に曝露された後の排ガス浄化用触媒組成物において顕著である。Ｃｅ系酸化物粒子に担持された触媒活性成分同士のシンタリングは、高温環境に曝露された後に生じやすいからである。なお、上限は、１００質量％から追加元素の酸化物換算量を差し引いた値である。 The Ce-based oxide particles are composed of a Ce-based oxide. The CeO2 equivalent amount of Ce in the Ce-based oxide particles is preferably 80% by mass or more, more preferably 85% by mass or more, and even more preferably 90% by mass or more, based on the mass of the Ce-based oxide particles. . This improves the affinity of the Ce-based oxide particles for the catalytically active component, and suppresses the occurrence of sintering between the catalytically active components carried on the Ce-based oxide particles. Therefore, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved. Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment. This is because sintering between the catalytically active components supported on the Ce-based oxide particles is likely to occur after exposure to a high-temperature environment. The upper limit is a value obtained by subtracting the amount of the additional element in terms of oxide from 100% by mass.
　Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量は、本発明の排ガス浄化用触媒組成物から得られた試料をエネルギー分散型Ｘ線分光法（ＥＤＳ（ＥＤＸとも呼ばれる））で分析し、得られた元素マッピングと、指定した粒子のＥＤＳ元素分析とから測定することができる。具体的には、元素マッピングにより定性的にＣｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びその他の粒子（例えば、Ａｌ系酸化物粒子）を識別（色分け）し、指定した粒子に対して組成分析（元素分析）することにより、指定した粒子における所定元素の酸化物換算量を測定することができる。 The CeO 2 equivalent amount of Ce in the Ce-based oxide particles is obtained by analyzing a sample obtained from the exhaust gas purification catalyst composition of the present invention by energy dispersive X-ray spectroscopy (EDS (also called EDX)). It can be determined from direct elemental mapping and EDS elemental analysis of specified particles. Specifically, by qualitatively identifying (color-coding) Ce-based oxide particles, Ce—Zr-based mixed oxide particles and other particles (for example, Al-based oxide particles) by elemental mapping, By performing a composition analysis (elemental analysis) with the specified particle, the oxide-equivalent amount of the predetermined element in the specified particles can be measured.
　触媒活性成分に対するＣｅ系酸化物粒子の親和性をより向上させ、Ｃｅ系酸化物粒子に担持された触媒活性成分同士のシンタリングの発生をより効果的に抑制する観点から、Ｃｅ系酸化物粒子におけるＺｒのＺｒＯ２換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは１０質量％未満、より好ましくは５質量％以下、より一層好ましくは３質量％以下、より一層好ましくは１質量％以下である。下限はゼロである。Ｃｅ系酸化物粒子におけるＺｒのＺｒＯ２換算量は、Ｃｅ－Ｚｒ系複合酸化物粒子におけるＺｒのＺｒＯ２換算量よりも小さく、かかる点から、Ｃｅ系酸化物粒子は、Ｃｅ－Ｚｒ系複合酸化物粒子と区別される。Ｃｅ系酸化物粒子におけるＺｒのＺｒＯ２換算量の測定方法は、Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量の測定方法と同様である。 Ce-based oxide particles from the viewpoint of further improving the affinity of the Ce-based oxide particles for the catalytically active component and more effectively suppressing the occurrence of sintering between the catalytically active components supported on the Ce-based oxide particles. is preferably less than 10% by mass, more preferably 5% by mass or less, even more preferably 3% by mass or less, still more preferably 1% by mass, based on the mass of the Ce - based oxide particles. % or less. The lower bound is zero. The ZrO 2 equivalent amount of Zr in the Ce-based oxide particles is smaller than the ZrO 2 equivalent amount of Zr in the Ce—Zr-based composite oxide particles. distinguished from matter particles. The method for measuring the ZrO2 equivalent amount of Zr in the Ce - based oxide particles is the same as the method for measuring the CeO2 equivalent amount of Ce in the Ce - based oxide particles.
　Ｃｅ系酸化物粒子は、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素を含む。すなわち、Ｃｅ系酸化物粒子は、Ｃｅと、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素とを含む複合酸化物である。なお、「追加元素」は、Ｃｅ及びＯ以外の元素を意味する。 The Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y and Nd. That is, the Ce-based oxide particles are composite oxides containing Ce and at least one additional element selected from Al, Mg, La, Pr, Y and Nd. In addition, the "additional element" means an element other than Ce and O.
　追加元素は、Ｃｅ及びＯとともに固溶体相を形成していてもよいし、結晶相又は非晶質相である単独相（例えば、追加元素の酸化物相）を形成していてもよいし、固溶体相及び単独相の両方を形成していてもよい。 The additional element may form a solid solution phase with Ce and O, may form a single phase that is a crystalline phase or an amorphous phase (for example, an oxide phase of the additional element), or may form a solid solution Both phases and single phases may be formed.
　Ｃｅ系酸化物粒子がＡｌ及びＭｇから選択される少なくとも１種の追加元素を含む場合、Ｃｅ系酸化物粒子の耐熱性が向上し、Ｃｅ系酸化物粒子の比表面積の低下及びそれに伴うＣｅ系酸化物粒子への触媒活性成分の埋没が抑制される。したがって、排ガス浄化用触媒組成物の比表面積が向上するとともに触媒活性成分の分散度が向上し、排ガス浄化用触媒組成物の排ガス浄化性能が向上する。かかる効果は、高温環境に曝露された後の排ガス浄化用触媒組成物において顕著である。Ｃｅ系酸化物粒子の比表面積の低下及びそれに伴うＣｅ系酸化物粒子への触媒活性成分の埋没は、高温環境に曝露された後に生じやすいからである。 When the Ce-based oxide particles contain at least one additional element selected from Al and Mg, the heat resistance of the Ce-based oxide particles is improved, the specific surface area of the Ce-based oxide particles is reduced, and the associated Ce-based The burial of the catalytically active component in the oxide particles is suppressed. Therefore, the specific surface area of the exhaust gas purifying catalyst composition is improved, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purifying performance of the exhaust gas purifying catalyst composition is improved. Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment. This is because the decrease in the specific surface area of the Ce-based oxide particles and the accompanying burial of the catalytically active component in the Ce-based oxide particles tend to occur after exposure to a high-temperature environment.
　Ｃｅ系酸化物粒子がＬａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素を含む場合、貴金属元素担持後のＣｅ系酸化物粒子の酸素貯蔵能（すなわち、排ガス中の酸素濃度が高い時には酸素を吸蔵し、排ガス中の酸素濃度が低い時には酸素を放出する能力）が向上する。したがって、排ガス中の酸素濃度の変動が緩和されて触媒活性成分の作動ウインドウが拡大し、排ガス浄化用触媒組成物の排ガス浄化能が向上する。 When the Ce-based oxide particles contain at least one additional element selected from La, Pr, Y and Nd, the oxygen storage capacity of the Ce-based oxide particles after supporting the noble metal element (i.e., the oxygen concentration in the exhaust gas is When the oxygen concentration in the exhaust gas is low, the ability to store oxygen is improved. Therefore, fluctuations in the oxygen concentration in the exhaust gas are mitigated, the operating window of the catalytically active component is expanded, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved.
　追加元素の上記作用をより効果的に発揮させる観点から、Ｃｅ系酸化物粒子における追加元素の酸化物換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．１質量％以上２０質量％以下である。「追加元素の酸化物換算量」は、Ａｌに関してはＡｌ２Ｏ３換算量を、Ｍｇに関してはＭｇＯ換算量を、Ｌａに関してはＬａ２Ｏ３換算量を、Ｐｒに関してはＰｒ６Ｏ１１換算量を、Ｙに関してはＹ２Ｏ３換算量を、Ｎｄに関してはＮｄ２Ｏ３換算量を意味する。また、「追加元素の酸化物換算量」は、Ｃｅ系酸化物粒子が１種の追加元素を含む場合には当該１種の追加元素の酸化物換算量を意味し、Ｃｅ系酸化物粒子が２種以上の追加元素を含む場合には当該２種以上の追加元素の酸化物換算量の合計を意味する。 From the viewpoint of more effectively exerting the above action of the additional element, the oxide conversion amount of the additional element in the Ce-based oxide particles is preferably 0.1% by mass or more based on the mass of the Ce-based oxide particles. % by mass or less. "Additional elements in terms of oxides" are Al 2 O 3 equivalents for Al, MgO equivalents for Mg, La 2 O 3 equivalents for La, and Pr 6 O 11 equivalents for Pr. , Y means the Y 2 O 3 equivalent amount, and Nd means the Nd 2 O 3 equivalent amount. Further, the "oxide equivalent amount of additional element" means the oxide equivalent amount of the one additional element when the Ce-based oxide particles contain one additional element, and the Ce-based oxide particles When two or more additional elements are included, it means the sum of the oxide-equivalent amounts of the two or more additional elements.
　Ｃｅ系酸化物粒子の耐熱性を向上させる観点から、Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量及び追加元素の酸化物換算量の合計は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは９０質量％以上、より好ましくは９５質量％以上、より一層好ましくは９８質量％以上である。なお、上限は１００質量％である。 From the viewpoint of improving the heat resistance of the Ce-based oxide particles, the total amount of Ce in terms of CeO2 and the amount of additional elements in terms of oxides in the Ce-based oxide particles is preferably based on the mass of the Ce-based oxide particles. is 90% by mass or more, more preferably 95% by mass or more, and still more preferably 98% by mass or more. In addition, an upper limit is 100 mass %.
　以下、Ａｌ及びＭｇから選択される追加元素を「第１追加元素」といい、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される追加元素を「第２追加元素」という。 Hereinafter, the additional element selected from Al and Mg will be referred to as "first additional element", and the additional element selected from La, Pr, Y and Nd will be referred to as "second additional element".
　一実施形態において、Ｃｅ系酸化物粒子は、少なくとも１種の第１追加元素を含み、第２追加元素を含まない。この実施形態において、第１追加元素の上記作用をより効果的に発揮させる観点から、Ｃｅ系酸化物粒子における第１追加元素の酸化物換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．１質量％以上２０質量％以下、より好ましくは０．１質量％以上１５質量％以下、より一層好ましくは０．１質量％以上１２質量％以下、より一層好ましくは０．１質量％以上１０質量％以下である。「第１追加元素の酸化物換算量」は、Ｃｅ系酸化物粒子が１種の第１追加元素を含む場合には当該１種の第１追加元素の酸化物換算量を意味し、Ｃｅ系酸化物粒子が２種の第１追加元素を含む場合には当該２種の第１追加元素の酸化物換算量の合計を意味する。 In one embodiment, the Ce-based oxide particles contain at least one first additional element and do not contain a second additional element. In this embodiment, from the viewpoint of more effectively exhibiting the above action of the first additional element, the oxide conversion amount of the first additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, Preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 15% by mass or less, still more preferably 0.1% by mass or more and 12% by mass or less, still more preferably 0.1% by mass % or more and 10% by mass or less. "Oxide conversion amount of the first additional element" means the oxide conversion amount of the first additional element when the Ce-based oxide particles contain the first additional element, and the Ce-based When the oxide particles contain two kinds of the first additional elements, it means the sum of the oxide-equivalent amounts of the two kinds of the first additional elements.
　別の実施形態において、Ｃｅ系酸化物粒子は、少なくとも１種の第２追加元素を含み、第１追加元素を含まない。この実施形態において、第２追加元素の上記作用をより効果的に発揮させる観点から、Ｃｅ系酸化物粒子における第２追加元素の酸化物換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．１質量％以上２０質量％以下、より好ましくは０．１質量％以上１５質量％以下、より一層好ましくは０．１質量％以上１２質量％以下、より一層好ましくは０．１質量％以上１０質量％以下である。「第２追加元素の酸化物換算量」は、Ｃｅ系酸化物粒子が１種の第２追加元素を含む場合には当該１種の第２追加元素の酸化物換算量を意味し、Ｃｅ系酸化物粒子が２種以上の第２追加元素を含む場合には当該２種以上の第２追加元素の酸化物換算量の合計を意味する。 In another embodiment, the Ce-based oxide particles contain at least one second additional element and do not contain the first additional element. In this embodiment, from the viewpoint of more effectively exerting the above action of the second additional element, the oxide conversion amount of the second additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, Preferably 0.1% by mass or more and 20% by mass or less, more preferably 0.1% by mass or more and 15% by mass or less, still more preferably 0.1% by mass or more and 12% by mass or less, still more preferably 0.1% by mass % or more and 10% by mass or less. "Oxide conversion amount of the second additional element" means the oxide conversion amount of the one type of second additional element when the Ce-based oxide particles contain one type of second additional element, and the Ce-based When the oxide particles contain two or more second additional elements, it means the sum of the oxide-equivalent amounts of the two or more second additional elements.
　さらに別の実施形態において、Ｃｅ系酸化物粒子は、少なくとも１種の第１追加元素と、少なくとも１種の第２追加元素とを含む。この実施形態において、第１及び第２追加元素の上記作用をより効果的に発揮させる観点から、Ｃｅ系酸化物粒子における第１追加元素の酸化物換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．１質量％以上１９．９質量％以下、より好ましくは０．１質量％以上１４．９質量％以下、より一層好ましくは０．１質量％以上１１．９質量％以下、より一層好ましくは０．１質量％以上９．９質量％以下であり、Ｃｅ系酸化物粒子における第２追加元素の酸化物換算量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．１質量％以上１９．９質量％以下、より好ましくは０．１質量％以上１４．９質量％以下、より一層好ましくは０．１質量％以上１１．９質量％以下、より一層好ましくは０．１質量％以上９．９質量％以下であり、Ｃｅ系酸化物粒子における第１及び第２追加元素の酸化物換算量の合計は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．２質量％以上２０質量％以下、より好ましくは０．５質量％以上１５質量％以下、より一層好ましくは１質量％以上１２質量％以下、より一層好ましくは２質量％以上１０質量％以下である。「第１追加元素の酸化物換算量」及び「第２追加元素の酸化物換算量」の意義は上記と同様である。 In yet another embodiment, the Ce-based oxide particles contain at least one first additional element and at least one second additional element. In this embodiment, from the viewpoint of more effectively exhibiting the above effects of the first and second additional elements, the oxide conversion amount of the first additional element in the Ce-based oxide particles is the mass of the Ce-based oxide particles. As a standard, preferably 0.1% by mass or more and 19.9% by mass or less, more preferably 0.1% by mass or more and 14.9% by mass or less, still more preferably 0.1% by mass or more and 11.9% by mass or less , Still more preferably 0.1% by mass or more and 9.9% by mass or less, and the oxide conversion amount of the second additional element in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, preferably 0.1% by mass or more and 19.9% by mass or less, more preferably 0.1% by mass or more and 14.9% by mass or less, still more preferably 0.1% by mass or more and 11.9% by mass or less, still more preferably It is 0.1% by mass or more and 9.9% by mass or less, and the total amount of oxide conversion of the first and second additional elements in the Ce-based oxide particles is based on the mass of the Ce-based oxide particles, preferably 0.2% by mass or more and 20% by mass or less, more preferably 0.5% by mass or more and 15% by mass or less, even more preferably 1% by mass or more and 12% by mass or less, still more preferably 2% by mass or more and 10% by mass or less is. The meanings of "the amount of the first additional element in terms of oxide" and "the amount of the second additional element in terms of oxide" are the same as above.
　Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径は、好ましくは７ｎｍ以上、より好ましくは１０ｎｍ以上、より一層好ましくは２０ｎｍ以上、より一層好ましくは３０ｎｍ以上である。これにより、Ｃｅ系酸化物粒子同士の凝集、Ｃｅ系酸化物粒子の小細孔の消失（すなわち比表面積の低下）及びそれらに伴うＣｅ系酸化物粒子への触媒活性成分の埋没が抑制される。したがって、触媒活性成分の分散度が向上し、排ガス浄化用触媒組成物の排ガス浄化性能が向上する。かかる効果は、高温環境に曝露された後の排ガス浄化用触媒組成物において顕著である。Ｃｅ系酸化物粒子同士の凝集、Ｃｅ系酸化物粒子の比表面積の低下及びそれらに伴うＣｅ系酸化物粒子への触媒活性成分の埋没は、高温環境に曝露された後に生じやすいからである。なお、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径の上限は、例えば２００ｎｍ、好ましくは１００ｎｍ、より好ましくは５５ｎｍである。これらの上限はそれぞれ、上記の下限のいずれと組み合わせてもよい。 The crystallite size of CeO 2 in the Ce-based oxide particles is preferably 7 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and still more preferably 30 nm or more. This suppresses the aggregation of the Ce-based oxide particles, the disappearance of the small pores of the Ce-based oxide particles (that is, the decrease in the specific surface area), and the accompanying burial of the catalytically active component in the Ce-based oxide particles. . Therefore, the degree of dispersion of the catalytically active component is improved, and the exhaust gas purification performance of the catalyst composition for exhaust gas purification is improved. Such an effect is remarkable in the exhaust gas purifying catalyst composition after being exposed to a high-temperature environment. This is because aggregation of Ce-based oxide particles, decrease in specific surface area of the Ce-based oxide particles, and accompanying burial of the catalytically active component in the Ce-based oxide particles tend to occur after exposure to a high-temperature environment. The upper limit of the crystallite size of CeO 2 in the Ce-based oxide particles is, for example, 200 nm, preferably 100 nm, and more preferably 55 nm. Each of these upper limits may be combined with any of the above lower limits.
　Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径の測定方法は、次の通りである。本発明の排ガス浄化用触媒組成物から得られた粉末試料及び市販のＸ線回折装置を使用してＸ線回折（ＸＲＤ）を行い、得られたＸＲＤパターンにおいて、ＣｅＯ２に由来するピークのうち、２θ＝５５～５８°に存在するピーク及び２θ＝４６～４９°に存在するピークを特定し、特定したピークに対してシェラーの式を適用し、結晶子径を測定する。具体的な測定方法は、実施例に記載の通りである。２θ＝５５～５８°に存在するピークから求めた結晶子径と、２θ＝４６～４９°に存在するピークから求めた結晶子径とを比較し、大きい方の結晶子径を、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径として選択する。得られたＸＲＤパターンにおいて、ＣｅＯ２以外の成分に由来するピークにより、ＣｅＯ２に由来するピークのうち、２θ＝５５～５８°に存在するピーク及び２θ＝４６～４９°に存在するピークのいずれか一方が特定できない場合には、特定できるピークから求めた結晶子径を、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径とする。 The method for measuring the crystallite size of CeO 2 in Ce-based oxide particles is as follows. X-ray diffraction (XRD) was performed using a powder sample obtained from the exhaust gas purifying catalyst composition of the present invention and a commercially available X-ray diffractometer, and in the obtained XRD pattern, among the peaks derived from CeO 2 , 2θ=55 to 58° and 2θ=46 to 49° are identified, and the Scherrer formula is applied to the identified peaks to measure the crystallite size. A specific measuring method is as described in Examples. The crystallite diameter obtained from the peak present at 2θ = 55 to 58° and the crystallite diameter obtained from the peak present at 2θ = 46 to 49° were compared, and the larger crystallite diameter was obtained by Ce-based oxidation. is chosen as the crystallite size of CeO 2 in the solid particles. In the obtained XRD pattern, the peaks derived from components other than CeO 2 , among the peaks derived from CeO 2 , either the peak existing at 2θ = 55 to 58° or the peak existing at 2θ = 46 to 49° If either one cannot be specified, the crystallite size obtained from the specified peak is taken as the crystallite size of CeO 2 in the Ce-based oxide particles.
　Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径は、例えば、Ｃｅ系酸化物粒子を製造する際の焼成条件を調整することにより調整してもよいし、Ｃｅ系酸化物粒子の製造段階において結晶化工程（例えば、水熱条件への曝露等）を設けることにより調整してもよい。 The crystallite diameter of CeO 2 in the Ce-based oxide particles may be adjusted, for example, by adjusting the firing conditions when producing the Ce-based oxide particles, or by adjusting the crystallite size in the production stage of the Ce-based oxide particles. It may be adjusted by providing a curing step (eg, exposure to hydrothermal conditions, etc.).
　Ｃｅ系酸化物粒子の上記作用効果をより効果的に発揮させる観点から、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは１．０質量％以上、より好ましくは２．０質量％以上、より一層好ましくは３．０質量％以上、より一層好ましくは５．０質量％以上、より一層好ましくは１０質量％以上である。また、Ｃｅ系酸化物粒子以外の成分の量（例えば、Ｃｅ－Ｚｒ系複合酸化物粒子の量、その他の粒子の量等）を相対的に増加させ、排ガス浄化用触媒組成物の比表面積（特に、高温環境に曝露された後の比表面積）をより向上させる観点から、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは５０質量％以下、より好ましくは３０質量％以下、より一層好ましくは２５質量％以下、より一層好ましくは２０質量％以下、より一層好ましくは１５質量％以下である。これらの上限はそれぞれ、上記の下限のいずれと組み合わせてもよい。 From the viewpoint of more effectively exhibiting the above effects of the Ce-based oxide particles, the amount of the Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention should be equal to the mass of the exhaust gas purifying catalyst composition of the present invention. As a standard, preferably 1.0% by mass or more, more preferably 2.0% by mass or more, even more preferably 3.0% by mass or more, still more preferably 5.0% by mass or more, and still more preferably 10% by mass % or more. In addition, the amount of components other than Ce-based oxide particles (for example, the amount of Ce-Zr-based composite oxide particles, the amount of other particles, etc.) is relatively increased, and the specific surface area of the exhaust gas purifying catalyst composition ( In particular, from the viewpoint of further improving the specific surface area after exposure to a high temperature environment, the amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is is preferably 50% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less, still more preferably 20% by mass or less, and even more preferably 15% by mass or less. Each of these upper limits may be combined with any of the above lower limits.
　本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量の測定方法は、次の（Ａ）～（Ｄ）の手順で行う。
（Ａ）排ガス浄化用触媒組成物から得られた試料について、誘導結合プラズマ発光分光分析法（ＩＣＰ）、蛍光Ｘ線分析法（ＸＲＦ）、走査型電子顕微鏡－エネルギー分散型Ｘ線分析法（ＳＥＭ－ＥＤＸ）等を使用して元素分析を行い、試料全体の構成元素の種類を特定するとともに、特定された各元素の含有率を酸化物換算で求める。
（Ｂ）排ガス浄化用触媒組成物から得られた試料について、ＳＥＭ観察及びＳＥＭ－ＥＤＸによる元素マッピングを行い、試料に含まれる粒子の種類（Ｃｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びその他の粒子（例えば、Ａｌ系酸化物粒子）を含む）を特定する。
（Ｃ）各種類の粒子について、任意に選択された複数個（例えば５０個）の粒子をＳＥＭ－ＥＤＸにて元素分析し、粒子の構成元素の種類を特定するとともに、特定された各元素の含有率を酸化物換算で求める。各種類の粒子について、各元素の含有率の平均値を各元素の含有率とする。
（Ｄ）試料における各元素の含有率と、各種類の粒子における各元素の含有率と、試料における各種類の粒子の含有率との関係を表す方程式を作成して解くことにより、試料における各種類の粒子の含有率を算出する。 The amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is measured by the following procedures (A) to (D).
(A) For the sample obtained from the exhaust gas purifying catalyst composition, inductively coupled plasma atomic emission spectrometry (ICP), X-ray fluorescence spectrometry (XRF), scanning electron microscope-energy dispersive X-ray spectrometry (SEM) -EDX) or the like is used to identify the types of constituent elements of the entire sample, and the content of each identified element is determined in terms of oxide.
(B) The sample obtained from the exhaust gas purification catalyst composition was subjected to SEM observation and elemental mapping by SEM-EDX, and the types of particles contained in the sample (Ce-based oxide particles, Ce-Zr-based composite oxide particles and other particles (including, for example, Al-based oxide particles).
(C) For each type of particles, a plurality of arbitrarily selected particles (for example, 50) are subjected to elemental analysis with SEM-EDX to identify the types of constituent elements of the particles, and each identified element. Calculate the content in terms of oxides. Let the average value of the content rate of each element be the content rate of each element for each kind of particles.
(D) each element in the sample, the content of each element in each type of particle, and the content of each type of particle in the sample by creating and solving an equation representing the relationship between the content of each element in the sample and the content of each type of particle in the sample Calculate the content of particles of each type.
　例えば、本発明の排ガス浄化用触媒組成物におけるＣｅ源、Ｚｒ源及びＡｌ源が、Ｃｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びＡｌ系酸化物粒子の３種のみからなる場合、次の通りに、Ｃｅ系酸化物粒子の量を求める。 For example, when the Ce source, Zr source, and Al source in the exhaust gas purifying catalyst composition of the present invention consist of only three types of Ce-based oxide particles, Ce—Zr-based composite oxide particles, and Al-based oxide particles, The amount of Ce-based oxide particles is determined as follows.
　先ず、本発明の排ガス浄化用触媒組成物から得られた試料について、任意に選択された５つの視野（各視野は２０個以上の粒子を含む）に対して、ＳＥＭ－ＥＤＸ分析をして、試料全体の構成元素の種類を特定するとともに、特定された各元素の含有率（平均値）を酸化物換算で求める。 First, a sample obtained from the exhaust gas purifying catalyst composition of the present invention was subjected to SEM-EDX analysis for five arbitrarily selected fields of view (each field of view contains 20 or more particles), The types of constituent elements of the entire sample are specified, and the content rate (average value) of each specified element is obtained in terms of oxide.
　次に、排ガス浄化用触媒組成物から得られた試料について、ＳＥＭ観察及びＳＥＭ－ＥＤＸによる元素マッピングを行い、試料に含まれる粒子の種類（Ｃｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びＡｌ系酸化物粒子を含む）を特定する。 Next, the sample obtained from the exhaust gas purifying catalyst composition was subjected to SEM observation and elemental mapping by SEM-EDX, and the types of particles contained in the sample (Ce-based oxide particles, Ce—Zr-based composite oxide particles and Al-based oxide particles).
　次に、各種類の粒子について、任意に選択された５０個の粒子をＳＥＭ－ＥＤＸにて元素分析し、粒子を構成する元素の種類を特定するとともに、特定された各元素の含有率（平均値）を酸化物換算で求める。 Next, for each type of particles, 50 arbitrarily selected particles are subjected to elemental analysis by SEM-EDX to identify the types of elements that make up the particles, and the content of each identified element (average value) in terms of oxide.
　以上の手順により、以下の含有率が求められる。
・試料全体におけるＣｅのＣｅＯ２換算での含有率（以下「ＰＴ」という。）
・Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算での含有率（以下「Ｐ１」という。）
・Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算での含有率（以下「Ｐ２」という。）
・Ａｌ系酸化物粒子におけるＣｅのＣｅＯ２換算での含有率（以下「Ｐ３」という。）
・試料全体におけるＺｒのＺｒＯ２換算での含有率（以下「ＱＴ」という。）
・Ｃｅ系酸化物粒子におけるＺｒのＺｒＯ２換算での含有率（以下「Ｑ１」という。）
・Ｃｅ－Ｚｒ系複合酸化物粒子におけるＺｒのＺｒＯ２換算での含有率（以下「Ｑ２」という。）
・Ａｌ系酸化物粒子におけるＺｒのＺｒＯ２換算での含有率（以下「Ｑ３」という。）
・試料全体におけるＡｌのＡｌ２Ｏ３換算での含有率（以下「ＲＴ」という。）
・Ｃｅ系酸化物粒子におけるＡｌのＡｌ２Ｏ３換算での含有率（以下「Ｒ１」という。）
・Ｃｅ－Ｚｒ系複合酸化物粒子におけるＡｌのＡｌ２Ｏ３換算での含有率（以下「Ｒ２」という。）
・Ａｌ系酸化物粒子におけるＡｌのＡｌ２Ｏ３換算での含有率（以下「Ｒ３」という。） According to the above procedure, the following contents are obtained.
- The content of Ce in the entire sample in terms of CeO2 ( hereinafter referred to as " PT ")
- Content of Ce in Ce-based oxide particles in terms of CeO 2 (hereinafter referred to as "P 1 ")
・The content of Ce in the Ce—Zr-based composite oxide particles in terms of CeO 2 (hereinafter referred to as “P 2 ”)
- Content of Ce in Al-based oxide particles in terms of CeO 2 (hereinafter referred to as "P 3 ")
・ Content of Zr in the entire sample in terms of ZrO 2 (hereinafter referred to as “Q T ”)
- The content of Zr in the Ce-based oxide particles in terms of ZrO2 ( hereinafter referred to as " Q1 ")
・The content of Zr in the Ce—Zr-based composite oxide particles in terms of ZrO 2 (hereinafter referred to as “Q 2 ”)
- Content of Zr in Al-based oxide particles in terms of ZrO2 ( hereinafter referred to as " Q3 ")
- The content of Al in terms of Al 2 O 3 in the entire sample (hereinafter referred to as “ RT ”)
- Content of Al in Ce-based oxide particles in terms of Al 2 O 3 (hereinafter referred to as “R 1 ”)
・ Content of Al in terms of Al 2 O 3 in Ce—Zr-based composite oxide particles (hereinafter referred to as “R 2 ”)
- The content of Al in Al-based oxide particles in terms of Al 2 O 3 (hereinafter referred to as “R 3 ”)
　次に、試料における各元素の含有率と、各種類の粒子における各元素の含有率と、試料における各種類の粒子の含有率との関係を表す方程式を作成して解くことにより、試料における各種類の粒子の含有率を算出する。 Next, by creating and solving an equation representing the relationship between the content of each element in the sample, the content of each element in each type of particle, and the content of each type of particle in the sample, each Calculate the content of particles of each type.
　具体的には、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びその他の粒子の含有率（質量基準）をＸ、Ｙ及びＺとすると、下記式（１）～（３）が成立する。
　ＰＴ＝Ｘ×Ｐ１＋Ｙ×Ｐ２＋Ｚ×Ｐ３　　　・・・（１）
　ＱＴ＝Ｘ×Ｑ１＋Ｙ×Ｑ２＋Ｚ×Ｑ３　　　・・・（２）
　ＲＴ＝Ｘ×Ｒ１＋Ｙ×Ｒ２＋Ｚ×Ｒ３　　　・・・（３） Specifically, if the contents (by mass) of Ce-based oxide particles, Ce--Zr-based mixed oxide particles and other particles in the exhaust gas purifying catalyst composition of the present invention are X, Y and Z, the following Equations (1) to (3) hold.
P T =X×P 1 +Y×P 2 +Z×P 3 (1)
Q T =X×Q 1 +Y×Q 2 +Z×Q 3 (2)
R T =X×R 1 +Y×R 2 +Z×R 3 (3)
　上記式（１）～（３）から、Ｘ、Ｙ及びＺを求め、Ｘから、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量を求める。 From the above formulas (1) to (3), X, Y and Z are obtained, and from X, the amount of Ce-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is obtained.
　Ｃｅ系酸化物粒子の平均粒子径が小さすぎると、Ｃｅ系酸化物粒子とＣｅ－Ｚｒ系複合酸化物粒子との界面で固相反応が進行し、Ｃｅ系酸化物粒子が粒子として存在できなくなる。Ｃｅ系酸化物粒子とＣｅ－Ｚｒ系複合酸化物粒子との界面での固相反応は、高温環境に曝露された後に生じやすい。一方、Ｃｅ系酸化物粒子の平均粒子径が大きすぎると、Ｃｅ系酸化物粒子の分散性が低下するとともに、Ｃｅ系酸化物粒子と触媒活性成分との接触性が低下する。したがって、Ｃｅ系酸化物粒子の上記作用効果をより効果的に発揮させる観点から、Ｃｅ系酸化物粒子の平均粒子径は、好ましくは０．１０μｍ以上１５μｍ以下、より好ましくは０．５０μｍ以上１２μｍ以下、より一層好ましくは１．０μｍ以上１０μｍ以下、より一層好ましくは２．０μｍ以上７．０μｍ以下である。 If the average particle size of the Ce-based oxide particles is too small, a solid phase reaction proceeds at the interface between the Ce-based oxide particles and the Ce—Zr-based composite oxide particles, and the Ce-based oxide particles cannot exist as particles. . A solid phase reaction at the interface between the Ce-based oxide particles and the Ce--Zr-based mixed oxide particles tends to occur after exposure to a high-temperature environment. On the other hand, if the average particle size of the Ce-based oxide particles is too large, the dispersibility of the Ce-based oxide particles is lowered, and the contact between the Ce-based oxide particles and the catalytically active component is lowered. Therefore, from the viewpoint of more effectively exerting the above effects of the Ce-based oxide particles, the average particle size of the Ce-based oxide particles is preferably 0.10 μm or more and 15 μm or less, more preferably 0.50 μm or more and 12 μm or less. , more preferably 1.0 μm or more and 10 μm or less, and still more preferably 2.0 μm or more and 7.0 μm or less.
　Ｃｅ系酸化物粒子の平均粒子径の測定方法は、次の通りである。本発明の排ガス浄化用触媒組成物から得られた試料を、走査型電子顕微鏡を使用して観察し、視野内から任意に選択された１００個のＣｅ系酸化物粒子の定方向径（フェレ径）を測定し、平均値をＣｅ系酸化物粒子の平均粒子径とする。なお、本発明の排ガス浄化用触媒組成物を製造する際、原料としてのＣｅ系酸化物粒子の平均粒子径は維持されるので、通常、Ｃｅ系酸化物粒子の平均粒子径は、原料としてのＣｅ系酸化物粒子の平均粒子径と同一である。 The method for measuring the average particle size of Ce-based oxide particles is as follows. A sample obtained from the exhaust gas purifying catalyst composition of the present invention was observed using a scanning electron microscope, and 100 Ce-based oxide particles arbitrarily selected from the field of view had a directional diameter (Ferret diameter ) are measured, and the average value is taken as the average particle diameter of the Ce-based oxide particles. When producing the exhaust gas purifying catalyst composition of the present invention, the average particle size of the Ce-based oxide particles as a raw material is maintained. It is the same as the average particle size of Ce-based oxide particles.
　Ｃｅ系酸化物粒子の平均粒子径は、例えば、ボールミル等の公知の粉砕方法を使用して調整してもよいし、Ｃｅ系酸化物粒子の製造時にスプレードライ製法等の造粒方法を使用して調整してもよい。 The average particle size of the Ce-based oxide particles may be adjusted, for example, by using a known pulverization method such as a ball mill, or by using a granulation method such as a spray drying method when producing the Ce-based oxide particles. can be adjusted.
　Ｃｅ系酸化物粒子は、触媒活性成分の担体として使用される。触媒活性成分の担持性を向上させる観点から、Ｃｅ系酸化物粒子は、多孔質であることが好ましい。Ｃｅ系酸化物粒子は、バインダとして使用されるセリア（以下「セリアバインダ」という。）と区別される。セリアバインダは、触媒組成物の材料として使用されるセリアゾル、又は、硝酸セリウム、硝酸セリウム等の水溶性のセリウム塩に由来する。 Ce-based oxide particles are used as carriers for catalytically active components. From the viewpoint of improving the supportability of the catalytically active component, the Ce-based oxide particles are preferably porous. Ce-based oxide particles are distinguished from ceria used as a binder (hereinafter referred to as "ceria binder"). The ceria binder is derived from a water-soluble cerium salt such as ceria sol or cerium nitrate or cerium nitrate used as a material for the catalyst composition.
　Ｃｅ系酸化物粒子は、Ｃｅ、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄ以外の１種又は２種以上の金属元素を含んでいてもよい。Ｃｅ、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄ以外の金属元素としては、例えば、Ｓｃ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ等の希土類元素、Ｆｅ、Ｍｎ、Ｎｉ、Ｚｒ等の遷移金属元素等が挙げられる。Ｃｅ、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄ以外の金属元素は、Ｃｅ及びＯとともに固溶体相を形成していてもよいし、結晶相又は非晶質相である単独相（例えば、金属元素の酸化物相）を形成していてもよいし、固溶体相及び単独相の両方を形成していてもよい。 The Ce-based oxide particles may contain one or more metal elements other than Ce, Al, Mg, La, Pr, Y and Nd. Examples of metal elements other than Ce, Al, Mg, La, Pr, Y and Nd include rare earth elements such as Sc, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, Fe, Examples include transition metal elements such as Mn, Ni, and Zr. Metal elements other than Ce, Al, Mg, La, Pr, Y, and Nd may form a solid solution phase with Ce and O, or may be a single phase that is a crystal phase or an amorphous phase (for example, metal elements oxide phase), or both a solid solution phase and a single phase may be formed.
＜Ｃｅ－Ｚｒ系複合酸化物粒子＞
　本発明の排ガス浄化用触媒組成物は、Ｃｅ－Ｚｒ系複合酸化物粒子を含む。なお、本明細書において、「Ｃｅ－Ｚｒ系複合酸化物粒子」は、別段規定される場合を除き、本発明の排ガス浄化用触媒組成物に含まれるＣｅ－Ｚｒ系複合酸化物粒子を意味し、本発明の排ガス浄化用触媒組成物の原料として使用されるＣｅ－Ｚｒ系複合酸化物粒子（以下「原料としてのＣｅ－Ｚｒ系複合酸化物粒子」という。）と区別される。 <Ce—Zr-based composite oxide particles>
The exhaust gas purifying catalyst composition of the present invention contains Ce—Zr composite oxide particles. In this specification, "Ce--Zr-based composite oxide particles" mean Ce--Zr-based composite oxide particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified. , and the Ce—Zr composite oxide particles used as raw materials for the exhaust gas purifying catalyst composition of the present invention (hereinafter referred to as “Ce—Zr composite oxide particles as raw materials”).
　Ｃｅ－Ｚｒ系複合酸化物粒子は、酸素貯蔵能（すなわち、排ガス中の酸素濃度が高い時には酸素を吸蔵し、排ガス中の酸素濃度が低い時には酸素を放出する能力）を有し、排ガス中の酸素濃度の変動を緩和して触媒活性成分の作動ウインドウを拡大する。したがって、排ガス浄化用触媒組成物の排ガス浄化能が向上する。 The Ce—Zr-based composite oxide particles have an oxygen storage capacity (that is, the ability to store oxygen when the oxygen concentration in the exhaust gas is high, and to release oxygen when the oxygen concentration in the exhaust gas is low). It mitigates fluctuations in oxygen concentration and expands the operating window of catalytically active components. Therefore, the exhaust gas purifying ability of the exhaust gas purifying catalyst composition is improved.
　Ｃｅ－Ｚｒ系複合酸化物粒子は、Ｃｅ－Ｚｒ系複合酸化物で構成されている。Ｃｅ－Ｚｒ系複合酸化物粒子の酸素貯蔵能を向上させる観点から、Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算量は、Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、好ましくは５質量％以上９０質量％以下、より好ましくは５質量％以上７０質量％以下、より一層好ましくは７質量％以上６０質量％以下、より一層好ましくは１０質量％以上５０質量％以下である。Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算量の測定方法は、Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量の測定方法と同様である。 The Ce—Zr-based composite oxide particles are composed of a Ce—Zr-based composite oxide. From the viewpoint of improving the oxygen storage capacity of the Ce—Zr-based composite oxide particles, the CeO 2 equivalent amount of Ce in the Ce—Zr-based composite oxide particles is preferably based on the mass of the Ce—Zr-based composite oxide particles. is 5% to 90% by mass, more preferably 5% to 70% by mass, even more preferably 7% to 60% by mass, and even more preferably 10% to 50% by mass. The method for measuring the CeO 2 equivalent amount of Ce in the Ce—Zr-based mixed oxide particles is the same as the method for measuring the CeO 2 equivalent amount of Ce in the Ce-based oxide particles.
　Ｃｅ－Ｚｒ系複合酸化物粒子の耐熱性をより向上させ、排ガス浄化用触媒組成物の排ガス浄化能（特に、高温環境に曝露された後の排ガス浄化能）をより向上させる観点から、Ｃｅ－Ｚｒ系複合酸化物粒子におけるＺｒのＺｒＯ２換算量は、Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、好ましくは１０質量％以上９５質量％以下、より好ましくは２０質量％以上９５質量％以下、より一層好ましくは４０質量％以上９５質量％以下、より一層好ましくは５０質量％以上９０質量％以下である。Ｃｅ－Ｚｒ系複合酸化物粒子におけるＺｒのＺｒＯ２換算量の測定方法は、Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量の測定方法と同様である。 From the viewpoint of further improving the heat resistance of the Ce—Zr-based composite oxide particles and further improving the exhaust gas purification performance of the exhaust gas purification catalyst composition (in particular, the exhaust gas purification performance after being exposed to a high-temperature environment), Ce- The ZrO2 equivalent amount of Zr in the Zr-based composite oxide particles is preferably 10% by mass or more and 95% by mass or less, more preferably 20% by mass or more and 95% by mass, based on the mass of the Ce—Zr-based composite oxide particles. Below, it is more preferably 40% by mass or more and 95% by mass or less, and still more preferably 50% by mass or more and 90% by mass or less. The method for measuring the ZrO 2 equivalent amount of Zr in the Ce—Zr-based composite oxide particles is the same as the method for measuring the CeO 2 equivalent amount of Ce in the Ce-based oxide particles.
　Ｃｅ－Ｚｒ系複合酸化物粒子の酸素貯蔵能及び耐熱性をより向上させ、排ガス浄化用触媒組成物の排ガス浄化能（特に、高温環境に曝露された後の排ガス浄化能）をより向上させる観点から、Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算量及びＺｒのＺｒＯ２換算量の合計は、Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、好ましくは７０質量％以上、より好ましくは７５質量％以上、より一層好ましくは８０質量％以上、より一層好ましくは８５質量％以上である。上限は、１００質量％である。 From the viewpoint of further improving the oxygen storage capacity and heat resistance of the Ce—Zr-based composite oxide particles, and further improving the exhaust gas purification performance (in particular, the exhaust gas purification performance after being exposed to a high-temperature environment) of the catalyst composition for exhaust gas purification. Therefore, the total amount of Ce in terms of CeO 2 and Zr in terms of ZrO 2 in the Ce—Zr-based mixed oxide particles is preferably 70% by mass or more, or more, based on the mass of the Ce—Zr-based mixed oxide particles. It is preferably 75% by mass or more, more preferably 80% by mass or more, and still more preferably 85% by mass or more. The upper limit is 100% by mass.
　Ｃｅ－Ｚｒ系複合酸化物粒子の上記作用効果をより効果的に発揮させる観点から、本発明の排ガス浄化用触媒組成物におけるＣｅ－Ｚｒ系複合酸化物粒子の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは５質量％以上、より好ましくは１５質量％以上、より一層好ましくは３０質量％以上である。また、Ｃｅ系酸化物粒子の量を相対的に増加させ、Ｃｅ系酸化物粒子の上記作用効果をより効果的に発揮させる観点から、本発明の排ガス浄化用触媒組成物におけるＣｅ－Ｚｒ系複合酸化物粒子の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは９８．９９質量％以下、より好ましくは８０質量％以下、より一層好ましくは７０質量％以下である。これらの上限はそれぞれ、上記の下限のいずれと組み合わせてもよい。本発明の排ガス浄化用触媒組成物におけるＣｅ－Ｚｒ系複合酸化物粒子の量の測定方法は、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量の測定方法と同様である。 From the viewpoint of more effectively exhibiting the above effects of the Ce—Zr-based composite oxide particles, the amount of the Ce—Zr-based composite oxide particles in the exhaust gas purifying catalyst composition of the present invention is Based on the weight of the catalyst composition, it is preferably 5% by weight or more, more preferably 15% by weight or more, and even more preferably 30% by weight or more. In addition, from the viewpoint of relatively increasing the amount of Ce-based oxide particles and more effectively exerting the above-mentioned effects of the Ce-based oxide particles, the Ce—Zr-based composite in the exhaust gas purifying catalyst composition of the present invention The amount of oxide particles is preferably 98.99% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less, based on the mass of the exhaust gas purifying catalyst composition of the present invention. Each of these upper limits may be combined with any of the above lower limits. The method for measuring the amount of Ce-Zr-based mixed oxide particles in the exhaust gas-purifying catalyst composition of the present invention is the same as the method for measuring the amount of Ce-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention.
　Ｃｅ系酸化物粒子の上記作用効果とＣｅ－Ｚｒ系複合酸化物粒子の上記作用効果とのバランスを図り、排ガス浄化用触媒組成物の排ガス浄化能（特に、高温環境に曝露された後の排ガス浄化性能）をより向上させる観点から、本発明の排ガス浄化用触媒組成物において、Ｃｅ－Ｚｒ系複合酸化物粒子の量の、Ｃｅ系酸化物粒子の量に対する比は、質量比で、好ましくは０．５以上７０以下、より好ましくは１．０以上２５以下、より一層好ましくは１．５以上１５以下である。 By balancing the above effects of the Ce-based oxide particles and the above-described effects of the Ce—Zr-based composite oxide particles, the exhaust gas purification performance of the catalyst composition for exhaust gas purification (in particular, exhaust gas after exposure to a high temperature environment purification performance), in the exhaust gas purifying catalyst composition of the present invention, the ratio of the amount of Ce—Zr-based composite oxide particles to the amount of Ce-based oxide particles is a mass ratio, preferably It is 0.5 or more and 70 or less, more preferably 1.0 or more and 25 or less, and still more preferably 1.5 or more and 15 or less.
　Ｃｅ－Ｚｒ系複合酸化物粒子の平均粒子径は、好ましくは０．１μｍ以上１５μｍ以下、より好ましくは０．５μｍ以上１２μｍ以下、より一層好ましくは１μｍ以上１０μｍ以下である。Ｃｅ－Ｚｒ系複合酸化物粒子の平均粒子径の測定方法は、Ｃｅ系酸化物粒子の平均粒子径の測定方法と同様である。Ｃｅ－Ｚｒ系複合酸化物粒子の平均粒子径は、Ｃｅ系酸化物粒子の平均粒子径と同様に調整することができる。なお、本発明の排ガス浄化用触媒組成物を製造する際、原料としてのＣｅ－Ｚｒ系複合酸化物粒子の平均粒子径は維持されるので、通常、Ｃｅ－Ｚｒ系複合酸化物粒子の平均粒子径は、原料としてのＣｅ－Ｚｒ系複合酸化物粒子の平均粒子径と同一である。 The average particle size of the Ce—Zr-based composite oxide particles is preferably 0.1 μm or more and 15 μm or less, more preferably 0.5 μm or more and 12 μm or less, and still more preferably 1 μm or more and 10 μm or less. The method for measuring the average particle size of the Ce—Zr-based composite oxide particles is the same as the method for measuring the average particle size of the Ce-based oxide particles. The average particle size of the Ce—Zr-based composite oxide particles can be adjusted in the same manner as the average particle size of the Ce-based oxide particles. When producing the exhaust gas purifying catalyst composition of the present invention, since the average particle size of the Ce—Zr-based mixed oxide particles as a raw material is maintained, the average particle size of the Ce—Zr-based mixed oxide particles is usually The diameter is the same as the average particle diameter of the Ce--Zr composite oxide particles as the raw material.
　Ｃｅ－Ｚｒ系複合酸化物粒子は、触媒活性成分の担体として使用される。触媒活性成分の担持性を向上させる観点から、Ｃｅ－Ｚｒ系複合酸化物粒子は、多孔質であることが好ましい。 The Ce-Zr-based composite oxide particles are used as a carrier for catalytically active components. From the viewpoint of improving the supportability of the catalytically active component, the Ce—Zr-based composite oxide particles are preferably porous.
　Ｃｅ－Ｚｒ系複合酸化物粒子において、Ｃｅ、Ｚｒ及びＯは固溶体相を形成していることが好ましい。Ｃｅ、Ｚｒ及びＯは、固溶体相に加えて、結晶相又は非晶質相である単独相（ＣｅＯ２相及び／又はＺｒＯ２相）を形成していてもよい。 Ce, Zr, and O preferably form a solid solution phase in the Ce—Zr-based composite oxide particles. Ce, Zr and O may form a single phase (CeO 2 phase and/or ZrO 2 phase), which is a crystalline phase or an amorphous phase, in addition to a solid solution phase.
　Ｃｅ－Ｚｒ系複合酸化物粒子は、Ｃｅ及びＺｒ以外の１種又は２種以上の金属元素を含んでいてもよい。Ｃｅ及びＺｒ以外の金属元素としては、例えば、Ｃｅ以外の希土類元素等が挙げられる。Ｃｅ以外の希土類元素としては、例えば、Ｙ、Ｐｒ、Ｓｃ、Ｌａ、Ｎｄ、Ｓｍ、Ｅｕ、Ｇｄ、Ｔｂ、Ｄｙ、Ｈｏ、Ｅｒ、Ｔｍ、Ｙｂ、Ｌｕ等が挙げられる。Ｃｅ及びＺｒ以外の金属元素は、Ｃｅ、Ｚｒ及びＯとともに、固溶体相を形成していてもよいし、結晶相又は非晶質相である単独相を形成していてもよいし、固溶体相及び単独相の両方を形成していてもよい。 The Ce—Zr-based composite oxide particles may contain one or more metal elements other than Ce and Zr. Metal elements other than Ce and Zr include, for example, rare earth elements other than Ce. Examples of rare earth elements other than Ce include Y, Pr, Sc, La, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. Metal elements other than Ce and Zr, together with Ce, Zr and O, may form a solid solution phase, may form a single phase that is a crystalline phase or an amorphous phase, may form a solid solution phase and Both single phases may be formed.
＜貴金属元素＞
　本発明の排ガス浄化用触媒組成物は、少なくとも１種の貴金属元素を含む。貴金属元素は、例えば、Ａｕ、Ａｇ、Ｐｔ、Ｐｄ、Ｒｈ、Ｉｒ、Ｒｕ、Ｏｓ等から選択することができるが、Ｒｈ及びＰｔから選択することが好ましい。 <Noble metal element>
The exhaust gas purifying catalyst composition of the present invention contains at least one precious metal element. The noble metal element can be selected from, for example, Au, Ag, Pt, Pd, Rh, Ir, Ru, Os, etc., and is preferably selected from Rh and Pt.
　貴金属元素は、触媒活性成分として機能し得る形態、例えば、金属、貴金属元素を含む合金、貴金属元素を含む化合物（例えば、貴金属元素の酸化物）等の形態で本発明の排ガス浄化用触媒組成物に含まれる。 The noble metal element is in a form capable of functioning as a catalytically active component, such as a metal, an alloy containing a noble metal element, a compound containing a noble metal element (e.g., an oxide of a noble metal element), and the like, in the exhaust gas purifying catalyst composition of the present invention. include.
　排ガス浄化性能とコストのバランスを図る観点から、本発明の排ガス浄化用触媒組成物における貴金属元素の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは０．０１０質量％以上２０質量％以下、より好ましくは０．０５０質量％以上１０質量％以下、より一層好ましくは０．１０質量％以上５．０質量％以下である。なお、本明細書において、「貴金属元素の量」は、触媒組成物が１種の貴金属元素を含む場合には当該１種の貴金属元素の金属換算量を意味し、触媒組成物が２種以上の貴金属元素を含む場合には当該２種以上の貴金属元素の金属換算量の合計を意味する。 From the viewpoint of balancing exhaust gas purifying performance and cost, the amount of the noble metal element in the exhaust gas purifying catalyst composition of the present invention is preferably 0.010% by mass based on the mass of the exhaust gas purifying catalyst composition of the present invention. 20 mass % or less, more preferably 0.050 mass % or more and 10 mass % or less, and still more preferably 0.10 mass % or more and 5.0 mass % or less. In the present specification, the "amount of noble metal element" means the metal-equivalent amount of the one noble metal element when the catalyst composition contains one noble metal element, and the catalyst composition contains two or more noble metal elements. When the noble metal element is included, it means the sum of the metal conversion amounts of the two or more noble metal elements.
　本発明の排ガス浄化用触媒組成物における貴金属元素の量は、本発明の排ガス浄化用触媒組成物から得られた試料をＥＤＳ又はＷＤＳ（波長分散型蛍光Ｘ線分析装置）で分析し、得られた元素マッピングと、指定した粒子のＥＤＳ元素分析とから測定することができる。 The amount of the noble metal element in the exhaust gas purifying catalyst composition of the present invention is obtained by analyzing a sample obtained from the exhaust gas purifying catalyst composition of the present invention with EDS or WDS (wavelength dispersive X-ray fluorescence spectrometer). It can be determined from direct elemental mapping and EDS elemental analysis of specified particles.
　貴金属元素は、Ｃｅ系酸化物粒子及びＣｅ－Ｚｒ系複合酸化物粒子に担持されていることが好ましい。低温～中温では、Ｃｅ系酸化物粒子に担持された貴金属元素による排ガス浄化性能が発揮されやすく、高温では、Ｃｅ－Ｚｒ系複合酸化物粒子に担持された貴金属元素の排ガス浄化性能が発揮されやすい。したがって、貴金属元素がＣｅ系酸化物粒子及びＣｅ－Ｚｒ系複合酸化物粒子に担持されていることにより、広い温度域において優れた排ガス浄化性能が発揮される。特に、本発明の排ガス浄化用触媒組成物では、高温環境に曝露された後、低温～中温において、優れた排ガス浄化性能が発揮される。なお、本明細書において、「低温～中温」は、例えば５０℃以上４００℃以下、好ましくは１００℃以上３５０℃以下の温度を意味する。「担持」は、貴金属等の触媒活性成分がＣｅ系酸化物粒子及びＣｅ－Ｚｒ系複合酸化物粒子の外表面又は細孔内表面に物理的又は化学的に吸着又は保持されている状態を意味する。例えば、本発明の排ガス浄化用触媒組成物から得られた試料をＳＥＭ－ＥＤＸで分析し、触媒活性成分とＣｅ系酸化物粒子とが同じ領域に存在している場合、触媒活性成分がＣｅ系酸化物粒子に担持されていると判断することができ、触媒活性成分とＣｅ－Ｚｒ系複合酸化物粒子とが同じ領域に存在している場合、触媒活性成分がＣｅ－Ｚｒ系複合酸化物粒子に担持されていると判断することができる。Ｃｅ系酸化物粒子に担持されている貴金属元素の量は、Ｃｅ系酸化物粒子の質量を基準として、好ましくは０．０５質量％以上、より好ましくは０．１０質量％以上である。上限は、例えば、２０質量％である。Ｃｅ－Ｚｒ系複合酸化物粒子に担持されている貴金属元素の量は、Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、好ましくは０．０５質量％以上、より好ましくは０．１０質量％以上である。上限は、例えば、２０質量％である。 The noble metal element is preferably supported on Ce-based oxide particles and Ce--Zr-based composite oxide particles. At low to medium temperatures, the exhaust gas purification performance of the noble metal element supported on the Ce-based oxide particles is likely to be exhibited, and at high temperatures, the exhaust gas purification performance of the noble metal element supported on the Ce—Zr-based composite oxide particles is likely to be exhibited. . Therefore, since the noble metal element is supported on the Ce-based oxide particles and the Ce--Zr-based composite oxide particles, excellent exhaust gas purifying performance is exhibited in a wide temperature range. In particular, the exhaust gas purifying catalyst composition of the present invention exhibits excellent exhaust gas purifying performance at low to medium temperatures after being exposed to a high-temperature environment. In this specification, "low temperature to medium temperature" means a temperature of, for example, 50°C or higher and 400°C or lower, preferably 100°C or higher and 350°C or lower. “Supported” means a state in which a catalytically active component such as a noble metal is physically or chemically adsorbed or held on the outer surface or inner surface of pores of Ce-based oxide particles and Ce—Zr-based mixed oxide particles. do. For example, a sample obtained from the exhaust gas purifying catalyst composition of the present invention is analyzed by SEM-EDX, and when the catalytically active component and Ce-based oxide particles are present in the same region, the catalytically active component is Ce-based It can be determined that they are supported on the oxide particles, and if the catalytically active component and the Ce—Zr-based composite oxide particles are present in the same region, the catalytically active component is the Ce—Zr-based composite oxide particles. It can be determined that the The amount of the noble metal element supported on the Ce-based oxide particles is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the mass of the Ce-based oxide particles. An upper limit is 20 mass %, for example. The amount of the noble metal element supported on the Ce—Zr composite oxide particles is preferably 0.05% by mass or more, more preferably 0.10% by mass, based on the mass of the Ce—Zr composite oxide particles. That's it. An upper limit is 20 mass %, for example.
＜その他の成分＞
　本発明の排ガス浄化用触媒組成物は、Ｃｅ系酸化物粒子及びＣｅ－Ｚｒ系複合酸化物粒子以外の１種又は２種以上の無機酸化物粒子（以下「その他の粒子」という。）を含んでいてもよい。なお、本明細書において、「その他の粒子」は、別段規定される場合を除き、本発明の排ガス浄化用触媒組成物に含まれるその他の粒子を意味し、本発明の排ガス浄化用触媒組成物の原料として使用されるその他の粒子（以下「原料としてのその他の粒子」という。）と区別される。 <Other ingredients>
The exhaust gas purifying catalyst composition of the present invention contains one or more inorganic oxide particles (hereinafter referred to as "other particles") other than Ce-based oxide particles and Ce--Zr-based composite oxide particles. You can stay. In the present specification, "other particles" means other particles contained in the exhaust gas purifying catalyst composition of the present invention, unless otherwise specified. (hereinafter referred to as "other particles as raw materials").
　その他の粒子は、Ｃｅ及びＺｒ以外の金属元素を含む酸化物で構成されている。その他の粒子としては、例えば、Ａｌ系酸化物粒子、ジルコニア粒子、シリカ粒子、チタニア粒子等が挙げられる。 　Other particles are composed of oxides containing metal elements other than Ce and Zr. Examples of other particles include Al-based oxide particles, zirconia particles, silica particles, titania particles, and the like.
　Ａｌ系酸化物粒子は、一般的に、Ｃｅ系酸化物粒子及びＣｅ－Ｚｒ系複合酸化物粒子よりも、耐熱性が高い。したがって、排ガス浄化用触媒組成物の比表面積（特に、高温環境に曝露された後の比表面積）が向上し、排ガス浄化用触媒組成物の排ガス浄化性能（特に、高温環境に曝露された後の排ガス浄化性能）が向上する。 Al-based oxide particles generally have higher heat resistance than Ce-based oxide particles and Ce--Zr-based composite oxide particles. Therefore, the specific surface area of the exhaust gas purifying catalyst composition (especially the specific surface area after exposure to a high temperature environment) is improved, and the exhaust gas purifying performance of the exhaust gas purifying catalyst composition (especially after exposure to a high temperature environment exhaust gas purification performance) is improved.
　Ａｌ系酸化物粒子は、Ａｌ系酸化物で構成されている。Ａｌ系酸化物粒子は、Ａｌ及びＯ以外の元素を含んでいてもよいし、含まなくてもよい。 The Al-based oxide particles are composed of Al-based oxides. The Al-based oxide particles may or may not contain elements other than Al and O.
　Ａｌ及びＯ以外の元素は、例えば、Ｂ、Ｓｉ、希土類元素（例えば、Ｙ、Ｃｅ、Ｌａ、Ｎｄ、Ｐｒ、Ｓｍ、Ｇｄ等）、Ｚｒ、Ｃｒ、アルカリ土類金属元素（例えば、Ｍｇ、Ｃａ、Ｓｒ、Ｂａ等）から選択することができるが、Ａｌ系酸化物の耐熱性を向上させる観点から、Ｃｅ、Ｌａ、Ｓｒ、Ｂａ等から選択することが好ましい。 Elements other than Al and O include, for example, B, Si, rare earth elements (e.g., Y, Ce, La, Nd, Pr, Sm, Gd, etc.), Zr, Cr, alkaline earth metal elements (e.g., Mg, Ca , Sr, Ba, etc.), but it is preferable to select from Ce, La, Sr, Ba, etc. from the viewpoint of improving the heat resistance of the Al-based oxide.
　Ａｌ系酸化物としては、例えば、アルミナ粒子（Ａｌ及びＯのみからなる酸化物）、アルミナの表面をＡｌ及びＯ以外の元素で修飾して得られる酸化物、アルミナ中にＡｌ及びＯ以外の元素を固溶して得られる酸化物等が挙げられる。Ａｌ及びＯ以外の元素を含むＡｌ系酸化物の具体例としては、アルミナ－シリカ、アルミナ－シリケート、アルミナ－ジルコニア、アルミナ－クロミア、アルミナ－セリア、アルミナ－ランタナ等が挙げられる。 Examples of Al-based oxides include alumina particles (oxides consisting only of Al and O), oxides obtained by modifying the surface of alumina with elements other than Al and O, and elements other than Al and O in alumina. and oxides obtained by solid solution. Specific examples of Al-based oxides containing elements other than Al and O include alumina-silica, alumina-silicate, alumina-zirconia, alumina-chromia, alumina-ceria, and alumina-lanthana.
　Ａｌ系酸化物粒子において、Ａｌ及びＯ以外の元素は、Ａｌ及びＯとともに固溶体相を形成していてもよいし、結晶相又は非晶質相である単独相（例えば、Ａｌ及びＯ以外の元素の酸化物相）を形成していてもよいし、固溶体相及び単独相の両方を形成していてもよい。 In the Al-based oxide particles, elements other than Al and O may form a solid solution phase together with Al and O, or a single phase that is a crystalline phase or an amorphous phase (e.g., elements other than Al and O oxide phase), or both a solid solution phase and a single phase may be formed.
　Ａｌ系酸化物粒子がＡｌ及びＯ以外の元素を含む場合、耐熱性を向上させる観点から、Ａｌ系酸化物粒子におけるＡｌのＡｌ２Ｏ３換算量は、Ａｌ系酸化物粒子の質量を基準として、好ましくは７０質量％以上９９．９質量％以下、より好ましくは８０質量％以上９９．５質量％以下、より一層好ましくは９０質量％以上９９質量％以下である。 When the Al-based oxide particles contain elements other than Al and O, from the viewpoint of improving heat resistance, the Al 2 O 3 equivalent amount of Al in the Al-based oxide particles is based on the mass of the Al-based oxide particles. , preferably 70% by mass or more and 99.9% by mass or less, more preferably 80% by mass or more and 99.5% by mass or less, and still more preferably 90% by mass or more and 99% by mass or less.
　比表面積（特に、高温環境に曝露された後の比表面積）を向上させるとともに、十分な助触媒（例えば、Ｃｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子等）の量を確保する観点から、本発明の排ガス浄化用触媒組成物におけるＡｌ系酸化物粒子の量は、本発明の排ガス浄化用触媒組成物の質量を基準として、好ましくは１０質量％以上９０質量％以下、より好ましくは１５質量％以上７０質量％以下、より一層好ましくは２０質量％以上６０質量％以下である。本発明の排ガス浄化用触媒組成物におけるＡｌ系酸化物粒子の量の測定方法は、本発明の排ガス浄化用触媒組成物におけるＣｅ系酸化物粒子の量の測定方法と同様である。 The viewpoint of improving the specific surface area (especially the specific surface area after exposure to a high temperature environment) and ensuring a sufficient amount of co-catalyst (eg, Ce-based oxide particles, Ce-Zr-based mixed oxide particles, etc.) Therefore, the amount of the Al-based oxide particles in the exhaust gas purifying catalyst composition of the present invention is preferably 10% by mass or more and 90% by mass or less, more preferably, based on the mass of the exhaust gas purifying catalyst composition of the present invention. 15% by mass or more and 70% by mass or less, more preferably 20% by mass or more and 60% by mass or less. The method for measuring the amount of Al-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention is the same as the method for measuring the amount of Ce-based oxide particles in the exhaust gas-purifying catalyst composition of the present invention.
　比表面積（特に、高温環境に曝露された後の比表面積）を向上させるとともに、十分な助触媒の量を確保する観点から、本発明の排ガス浄化用触媒組成物において、Ａｌ系酸化物粒子の量の、Ｃｅ系酸化物粒子の量に対する比は、質量比で、好ましくは０．１以上１０以下、より好ましくは０．２以上５以下、より一層好ましくは０．３以上３以下である。 From the viewpoint of improving the specific surface area (particularly, the specific surface area after being exposed to a high-temperature environment) and securing a sufficient amount of the co-catalyst, the catalyst composition for exhaust gas purification of the present invention contains Al-based oxide particles. The ratio of the amount to the amount of the Ce-based oxide particles is preferably 0.1 or more and 10 or less, more preferably 0.2 or more and 5 or less, and still more preferably 0.3 or more and 3 or less, in mass ratio.
　Ａｌ系酸化物粒子の耐熱性と、基材への塗工性とを両立させる観点から、Ａｌ系酸化物粒子の平均粒子径は、好ましくは１μｍ以上５０μｍ以下、より好ましくは２μｍ以上３０μｍ以下、より一層好ましくは４μｍ以上２０μｍ以下である。Ａｌ系酸化物粒子の平均粒子径の測定方法は、Ｃｅ系酸化物粒子の平均粒子径の測定方法と同様である。Ａｌ系酸化物粒子の平均粒子径は、Ｃｅ系酸化物粒子の平均粒子径と同様に調整することができる。なお、本発明の排ガス浄化用触媒組成物を製造する際、原料としてのＡｌ系酸化物粒子の平均粒子径は維持されるので、通常、Ａｌ系酸化物粒子の平均粒子径は、原料としてのＡｌ系酸化物粒子の平均粒子径と同一である。 From the viewpoint of achieving both the heat resistance of the Al-based oxide particles and the coatability to the substrate, the average particle size of the Al-based oxide particles is preferably 1 μm or more and 50 μm or less, more preferably 2 μm or more and 30 μm or less. More preferably, it is 4 μm or more and 20 μm or less. The method for measuring the average particle size of the Al-based oxide particles is the same as the method for measuring the average particle size of the Ce-based oxide particles. The average particle size of the Al-based oxide particles can be adjusted in the same manner as the average particle size of the Ce-based oxide particles. When producing the exhaust gas purifying catalyst composition of the present invention, since the average particle size of the Al-based oxide particles as the raw material is maintained, the average particle size of the Al-based oxide particles is usually the same as that of the raw material. It is the same as the average particle size of Al-based oxide particles.
　その他の粒子は、触媒活性成分の担体として使用される。触媒活性成分の担持性を向上させる観点から、その他の粒子は、多孔質であることが好ましい。Ａｌ系酸化物粒子は、バインダとして使用されるアルミナ（以下「アルミナバインダ」という。）とは区別される。アルミナバインダは、触媒組成物の材料として使用されるアルミナゾルに由来する。 Other particles are used as carriers for catalytically active components. From the viewpoint of improving the supportability of the catalytically active component, the other particles are preferably porous. Al-based oxide particles are distinguished from alumina used as a binder (hereinafter referred to as "alumina binder"). Alumina binder originates from the alumina sol used as a material of the catalyst composition.
　本発明の排ガス浄化用触媒組成物がその他の粒子を含む場合、貴金属元素は、その他の粒子に担持されていてもよい。「担持」の意義は上記と同様である。高温では、その他の粒子に担持された貴金属元素の排ガス浄化性能が発揮されやすい。したがって、貴金属元素がＣｅ系酸化物粒子、Ｃｅ－Ｚｒ系複合酸化物粒子及びその他の粒子に担持されていることにより、広い温度域における排ガス浄化性能が向上する。その他の粒子に担持されている貴金属元素の量は、その他の粒子の質量を基準として、好ましくは０．０５質量％以上、より好ましくは０．１０質量％以上である。なお、上限は、例えば、２０質量％である。 When the exhaust gas purifying catalyst composition of the present invention contains other particles, the noble metal element may be supported on the other particles. The meaning of "carrying" is the same as above. At high temperatures, the exhaust gas purifying performance of the noble metal elements supported on the other particles is likely to be exhibited. Therefore, by supporting the noble metal element on the Ce-based oxide particles, the Ce--Zr-based mixed oxide particles and other particles, the exhaust gas purification performance is improved in a wide temperature range. The amount of the noble metal element carried on the other particles is preferably 0.05% by mass or more, more preferably 0.10% by mass or more, based on the mass of the other particles. In addition, an upper limit is 20 mass %, for example.
　本発明の排ガス浄化用触媒組成物は、安定剤、バインダ等を含んでいてもよい。バインダとしては、例えば、アルミナゾル、ジルコニアゾル、チタニアゾル、シリカゾル等の無機酸化物系バインダが挙げられる。安定剤としては、例えば、アルカリ土類金属元素（例えば、Ｓｒ、Ｂａ等）の硝酸塩、炭酸塩、酸化物、硫酸塩等が挙げられる。 The exhaust gas purifying catalyst composition of the present invention may contain stabilizers, binders, and the like. Examples of the binder include inorganic oxide binders such as alumina sol, zirconia sol, titania sol and silica sol. Examples of stabilizers include nitrates, carbonates, oxides and sulfates of alkaline earth metal elements (eg, Sr, Ba, etc.).
＜排ガス浄化用触媒組成物の形態＞
　本発明の排ガス浄化用触媒組成物の形態は、例えば、粉末状、成形体状、層状である。 <Form of Exhaust Gas Purifying Catalyst Composition>
The form of the exhaust gas purifying catalyst composition of the present invention is, for example, a powder, a compact, or a layer.
＜排ガス浄化用触媒組成物の製造方法＞
　本発明の排ガス浄化用触媒組成物は、例えば、貴金属塩含有溶液と、原料としてのＣｅ系酸化物粒子と、原料としてのＣｅ－Ｚｒ系複合酸化物粒子と、必要に応じてその他の成分（例えば、原料としてのその他の粒子、バインダ、安定剤等）とを混合した後、乾燥し、焼成することにより製造することができる。焼成物は、必要に応じて粉砕してもよい。貴金属塩としては、例えば、硝酸塩、アンミン錯体塩、塩化物等が挙げられる。貴金属塩含有溶液の溶媒は、例えば、水（例えば、イオン交換水等）である。貴金属塩含有溶液は、アルコール等の有機溶媒を含んでいてもよい。乾燥温度は、例えば５０℃以上１５０℃以下であり、乾燥時間は、例えば１時間以上３時間以下である。焼成温度は、例えば３００℃以上７００℃以下であり、焼成時間は、例えば１時間以上３時間以下である。焼成は、例えば、大気雰囲気下で行うことができる。 <Method for Producing Exhaust Gas Purifying Catalyst Composition>
The exhaust gas purifying catalyst composition of the present invention comprises, for example, a noble metal salt-containing solution, Ce-based oxide particles as a raw material, Ce--Zr-based composite oxide particles as a raw material, and optionally other components ( For example, it can be produced by mixing other particles, binders, stabilizers, etc. as raw materials, followed by drying and firing. The fired product may be pulverized as necessary. Examples of noble metal salts include nitrates, ammine complex salts, chlorides, and the like. The solvent of the noble metal salt-containing solution is, for example, water (eg, ion-exchanged water, etc.). The noble metal salt-containing solution may contain an organic solvent such as alcohol. The drying temperature is, for example, 50° C. or higher and 150° C. or lower, and the drying time is, for example, 1 hour or longer and 3 hours or shorter. The firing temperature is, for example, 300° C. or higher and 700° C. or lower, and the firing time is, for example, 1 hour or longer and 3 hours or shorter. Firing can be performed, for example, in an air atmosphere.
　Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径を所望の範囲に調整する観点から、原料としてのＣｅ系酸化物粒子に熱負荷を与え、原料としてのＣｅ系酸化物粒子におけるＣｅＯ２の結晶子径を調整することが好ましい。熱負荷は、例えば、１０００℃で１時間、大気雰囲気下で焼成することにより行うことができる。原料としてのＣｅ系酸化物粒子におけるＣｅＯ２の結晶子径は、好ましくは７ｎｍ以上、より好ましくは１０ｎｍ以上、より一層好ましくは２０ｎｍ以上、より一層好ましくは３０ｎｍ以上である。原料としてのＣｅ系酸化物粒子におけるＣｅＯ２の結晶子径の上限は、例えば２００ｎｍ、好ましくは１００ｎｍ、より好ましくは５５ｎｍである。これらの上限はそれぞれ、上記の下限のいずれと組み合わせてもよい。原料としてのＣｅ系酸化物粒子におけるＣｅＯ２の結晶子径の測定方法は、原料としてのＣｅ系酸化物粒子を使用して測定を行う点を除き、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径の測定方法と同様である。 From the viewpoint of adjusting the crystallite diameter of CeO 2 in the Ce-based oxide particles to a desired range, a heat load is applied to the Ce-based oxide particles as a raw material, and the crystallites of CeO 2 in the Ce-based oxide particles as a raw material It is preferable to adjust the diameter. A heat load can be applied, for example, by firing at 1000° C. for 1 hour in an air atmosphere. The crystallite size of CeO 2 in the Ce-based oxide particles as a raw material is preferably 7 nm or more, more preferably 10 nm or more, still more preferably 20 nm or more, and still more preferably 30 nm or more. The upper limit of the crystallite size of CeO 2 in the Ce-based oxide particles as a raw material is, for example, 200 nm, preferably 100 nm, more preferably 55 nm. Each of these upper limits may be combined with any of the above lower limits. The method for measuring the crystallite size of CeO2 in Ce - based oxide particles as a raw material is the crystallite size of CeO2 in Ce - based oxide particles, except that the measurement is performed using the Ce-based oxide particles as a raw material. It is the same as the diameter measurement method.
≪排ガス浄化用触媒≫
　以下、本発明の排ガス浄化用触媒について説明する。 ≪Exhaust gas purification catalyst≫
The exhaust gas purifying catalyst of the present invention will be described below.
　本発明の排ガス浄化用触媒は、基材と、該基材に設けられた本発明の触媒層とを備える。本発明の排ガス浄化用触媒は、本発明の触媒層の下側、上側、下流側及び上流側から選択された１以上の位置に、本発明の触媒層以外の触媒層を備えていてもよい。 The exhaust gas purifying catalyst of the present invention comprises a substrate and the catalyst layer of the present invention provided on the substrate. The exhaust gas purifying catalyst of the present invention may have a catalyst layer other than the catalyst layer of the present invention at one or more positions selected from the lower side, the upper side, the downstream side, and the upstream side of the catalyst layer of the present invention. .
＜基材＞
　基材は、排ガス浄化用触媒の基材として一般的に使用されている基材から適宜選択することができる。基材としては、例えば、ウォールフロー型基材、フロースルー型基材等が挙げられる。 <Base material>
The base material can be appropriately selected from base materials generally used as base materials for exhaust gas purification catalysts. Examples of substrates include wall-flow type substrates and flow-through type substrates.
　基材を構成する材料は、排ガス浄化用触媒の基材の材料として一般的に使用されている材料から適宜選択することができる。基材を構成する材料は、基材が例えば４００℃以上の排ガスに曝露された場合にも基材の形状が安定して維持され得る材料であることが好ましい。基材の材料としては、例えば、コージェライト、炭化ケイ素（ＳｉＣ）、チタン酸アルミニウム等のセラミックス、ステンレス鋼等の合金等が挙げられる。 The material that constitutes the base material can be appropriately selected from materials that are generally used as base materials for exhaust gas purification catalysts. The material constituting the base material is preferably a material that can stably maintain the shape of the base material even when the base material is exposed to exhaust gas of 400° C. or higher, for example. Materials for the substrate include, for example, cordierite, silicon carbide (SiC), ceramics such as aluminum titanate, and alloys such as stainless steel.
＜触媒層＞
　本発明の触媒層は、本発明の排ガス浄化用触媒組成物で構成されている。すなわち、本発明の触媒層は、Ｃｅ系酸化物粒子と、Ｃｅ－Ｚｒ系複合酸化物粒子と、貴金属元素とを含む。上記の＜Ｃｅ系酸化物粒子＞、＜Ｃｅ－Ｚｒ系複合酸化物粒子＞、＜貴金属元素＞及び＜その他の成分＞の欄における説明は、本発明の触媒層にも適用される。適用の際、「本発明の排ガス浄化用触媒組成物」は、「本発明の触媒層」に読み替えられる。 <Catalyst layer>
The catalyst layer of the present invention is composed of the exhaust gas purifying catalyst composition of the present invention. That is, the catalyst layer of the present invention contains Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element. The explanations in the above sections of <Ce-based oxide particles>, <Ce--Zr-based mixed oxide particles>, <Noble metal element> and <Other components> also apply to the catalyst layer of the present invention. At the time of application, "the exhaust gas purifying catalyst composition of the present invention" is read as "the catalyst layer of the present invention".
　排ガス浄化性能とコストとのバランスを図る観点から、基材の単位体積当たりの本発明の触媒層の質量（乾燥及び焼成後の質量）は、好ましくは１０ｇ／Ｌ以上３００ｇ／Ｌ以下、より好ましくは３０ｇ／Ｌ以上２００ｇ／Ｌ以下、より一層好ましくは５０ｇ／Ｌ以上１５０ｇ／Ｌ以下である。なお、基材の体積は、基材の見かけの体積を意味する。例えば、基材が外径２ｒの円柱状である場合、基材の体積は、式：基材の体積＝π×ｒ２×（基材の長さ）で表される。 From the viewpoint of balancing exhaust gas purification performance and cost, the mass of the catalyst layer of the present invention per unit volume of the substrate (mass after drying and firing) is preferably 10 g/L or more and 300 g/L or less, more preferably. is 30 g/L or more and 200 g/L or less, more preferably 50 g/L or more and 150 g/L or less. In addition, the volume of a base material means the apparent volume of a base material. For example, when the substrate is cylindrical with an outer diameter of 2r, the volume of the substrate is represented by the formula: volume of substrate=π×r 2 ×(length of substrate).
＜第１実施形態＞
　以下、図１～４に基づいて、本発明の第１実施形態に係る排ガス浄化用触媒１Ａについて説明する。 <First embodiment>
An exhaust gas purifying catalyst 1A according to a first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. FIG.
　図１に示すように、排ガス浄化用触媒１Ａは、内燃機関の排気管Ｐ内の排気通路に配置されている。内燃機関は、例えば、ガソリンエンジン等である。内燃機関から排出された排ガスは、排気管Ｐの一端から他端に向けて排気管Ｐ内の排気通路を流通し、排気管Ｐ内に設けられた排ガス浄化用触媒１Ａで浄化される。図面において、排ガス流通方向は、符号Ｘで示されている。本明細書において、排ガス流通方向Ｘの上流側を「排ガス流入側」、排ガス流通方向Ｘの下流側を「排ガス流出側」という場合がある。 As shown in FIG. 1, an exhaust gas purifying catalyst 1A is arranged in an exhaust passage within an exhaust pipe P of an internal combustion engine. The internal combustion engine is, for example, a gasoline engine or the like. Exhaust gas discharged from the internal combustion engine flows through an exhaust passage in the exhaust pipe P from one end to the other end of the exhaust pipe P, and is purified by the exhaust gas purification catalyst 1A provided in the exhaust pipe P. In the drawings, the exhaust gas flow direction is indicated by X. In this specification, the upstream side in the exhaust gas flow direction X may be referred to as the "exhaust gas inflow side", and the downstream side in the exhaust gas flow direction X may be referred to as the "exhaust gas outflow side".
　排気管Ｐ内の排気通路には、排ガス浄化用触媒１Ａとともに、その他の排ガス浄化用触媒が配置されていてもよい。例えば、排気管Ｐ内の排気通路の上流側に、排ガス浄化用触媒１Ａが配置され、排気管Ｐ内の排気通路の下流側に、その他の排ガス浄化用触媒が配置されていてもよい。その他の排ガス浄化用触媒としては、例えば、後述する排ガス浄化用触媒１Ｂ等が挙げられる。 In addition to the exhaust gas purifying catalyst 1A, other exhaust gas purifying catalysts may be arranged in the exhaust passage in the exhaust pipe P. For example, the exhaust gas purifying catalyst 1A may be arranged on the upstream side of the exhaust passage in the exhaust pipe P, and another exhaust gas purifying catalyst may be arranged on the downstream side of the exhaust passage in the exhaust pipe P. Other exhaust gas purifying catalysts include, for example, an exhaust gas purifying catalyst 1B, which will be described later.
　図２～４に示すように、排ガス浄化用触媒１Ａは、基材１０と、基材１０上に設けられた触媒層２０とを備える。 As shown in FIGS. 2 to 4, the exhaust gas purifying catalyst 1A includes a substrate 10 and a catalyst layer 20 provided on the substrate 10. As shown in FIGS.
　基材に関する上記説明は、基材１０にも適用される。 The above description regarding the base material also applies to the base material 10.
　触媒層２０は、本発明の排ガス浄化用触媒組成物で構成されている。すなわち、触媒層２０は、Ｃｅ系酸化物粒子と、Ｃｅ－Ｚｒ系複合酸化物粒子と、貴金属元素とを含む。本発明の触媒層に関する上記説明は、触媒層２０にも適用される。 The catalyst layer 20 is composed of the exhaust gas purifying catalyst composition of the present invention. That is, the catalyst layer 20 contains Ce-based oxide particles, Ce--Zr-based composite oxide particles, and noble metal elements. The above description of the catalyst layer of the present invention also applies to catalyst layer 20 .
　図２～４に示すように、基材１０は、基材１０の外形を規定する筒状部１１と、筒状部１１内に設けられた隔壁部１２と、隔壁部１２によって仕切られたセル１３とを有する。 As shown in FIGS. 2 to 4, the substrate 10 includes a tubular portion 11 that defines the outer shape of the substrate 10, partition walls 12 provided in the tubular portion 11, and cells partitioned by the partition walls 12. 13.
　図２に示すように、筒状部１１の形状は、円筒状であるが、楕円筒状、多角筒状等のその他の形状であってもよい。 As shown in FIG. 2, the tubular portion 11 has a cylindrical shape, but may have other shapes such as an elliptical tubular shape and a polygonal tubular shape.
　図２～４に示すように、隣接するセル１３の間には隔壁部１２が存在し、隣接するセル１３は隔壁部１２によって仕切られている。隔壁部１２は、多孔質であることが好ましい。隔壁部１２の厚みは、例えば２０μｍ以上１５００μｍ以下である。 As shown in FIGS. 2 to 4, partition walls 12 exist between adjacent cells 13, and the adjacent cells 13 are partitioned by the partition walls 12. The partition wall 12 is preferably porous. The thickness of the partition 12 is, for example, 20 μm or more and 1500 μm or less.
　図４に示すように、セル１３は、排ガス流通方向Ｘに延在しており、排ガス流入側の端部及び排ガス流出側の端部を有する。 As shown in FIG. 4, the cell 13 extends in the exhaust gas flow direction X and has an exhaust gas inflow side end and an exhaust gas outflow side end.
　図４に示すように、セル１３の排ガス流入側の端部及び排ガス流出側の端部はともに開口している。したがって、セル１３の排ガス流入側の端部（開口部）から流入した排ガスは、セル１３の排ガス流出側の端部（開口部）から流出する。このような様式は、フロースルー型と呼ばれる。 As shown in FIG. 4, both the end on the exhaust gas inflow side and the exhaust gas outflow side of the cell 13 are open. Therefore, the exhaust gas that has flowed in from the end (opening) of the cell 13 on the exhaust gas inflow side flows out from the end (opening) of the cell 13 on the exhaust gas outflow side. Such a mode is called a flow-through type.
　図２及び３に示すように、セル１３の排ガス流入側の端部（開口部）の平面視形状は、四角形であるが、六角形、八角形等のその他の形状であってもよい。セル１３の排ガス流出側の端部（開口部）の平面視形状も同様である。 As shown in FIGS. 2 and 3, the planar view shape of the end (opening) of the cell 13 on the exhaust gas inflow side is quadrangular, but it may be hexagonal, octagonal, or other shape. The planar view shape of the end (opening) of the cell 13 on the exhaust gas outflow side is the same.
　基材１０の１平方インチあたりのセル密度は、例えば３００セル以上９００セル以下である。なお、基材１０の１平方インチあたりのセル密度は、基材１０を排ガス流通方向Ｘと垂直な平面で切断して得られた断面における１平方インチあたりのセル１３の合計個数である。 The cell density per square inch of the substrate 10 is, for example, 300 cells or more and 900 cells or less. The cell density per square inch of the base material 10 is the total number of cells 13 per square inch in a cross section obtained by cutting the base material 10 along a plane perpendicular to the flow direction X of the exhaust gas.
　図４に示すように、触媒層２０は、基材１０の隔壁部１２上に設けられている。 As shown in FIG. 4, the catalyst layer 20 is provided on the partition wall portion 12 of the substrate 10 .
　図４に示すように、触媒層２０は、隔壁部１２の排ガス流入側の端部から隔壁部１２の排ガス流出側の端部まで排ガス流通方向Ｘに沿って延在している。触媒層２０は、隔壁部１２の排ガス流出側の端部に至らないように、隔壁部１２の排ガス流入側の端部から排ガス流通方向Ｘに沿って延在していてもよいし、隔壁部１２の排ガス流入側の端部に至らないように、隔壁部１２の排ガス流出側の端部から排ガス流通方向Ｘとは反対の方向に沿って延在していてもよい。 As shown in FIG. 4 , the catalyst layer 20 extends along the exhaust gas flow direction X from the exhaust gas inflow side end of the partition wall 12 to the exhaust gas outflow side end of the partition wall 12 . The catalyst layer 20 may extend along the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas inflow side so as not to reach the end of the partition wall 12 on the exhaust gas outflow side. It may extend from the end of the partition wall 12 on the exhaust gas outflow side along the direction opposite to the exhaust gas flow direction X so as not to reach the exhaust gas inflow side end of the partition wall portion 12 .
　排ガス浄化用触媒１Ａは、基材１０の隔壁部１２上に触媒層２０を形成することにより製造することができる。例えば、貴金属塩含有溶液と、原料としてのＣｅ系酸化物粒子と、原料としてのＣｅ－Ｚｒ系複合酸化物粒子と、必要に応じてその他の成分（例えば、原料としてのその他の粒子、バインダ、安定剤等）とを混合してスラリーを調製し、スラリーを基材１０の隔壁部１２上に塗布し、乾燥し、焼成することにより、基材１０の隔壁部１２上に触媒層２０を形成することができる。貴金属塩、貴金属塩含有溶液の溶媒、乾燥条件、焼成条件、原料としてのＣｅ系酸化物粒子におけるＣｅＯ２の結晶子径等は、本発明の排ガス浄化用触媒組成物の製造方法と同様である。 The exhaust gas purifying catalyst 1A can be manufactured by forming the catalyst layer 20 on the partition wall portion 12 of the substrate 10 . For example, a noble metal salt-containing solution, Ce-based oxide particles as raw materials, Ce—Zr-based composite oxide particles as raw materials, and optionally other components (for example, other particles as raw materials, binders, Stabilizer, etc.) is mixed to prepare a slurry, the slurry is applied on the partition wall portion 12 of the substrate 10, dried, and fired to form the catalyst layer 20 on the partition wall portion 12 of the substrate 10. can do. The noble metal salt, the solvent of the noble metal salt-containing solution, the drying conditions, the calcining conditions, the crystallite size of CeO2 in the Ce - based oxide particles as the raw material, etc. are the same as in the method for producing the exhaust gas purifying catalyst composition of the present invention. .
＜第２実施形態＞
　以下、図５に基づいて、本発明の第２実施形態に係る排ガス浄化用触媒１Ｂについて説明する。排ガス浄化用触媒１Ｂにおいて、排ガス浄化用触媒１Ａと同一の部材は、排ガス浄化用触媒１Ａと同一の符号で示されている。以下で別段記載する場合を除き、排ガス浄化用触媒１Ａに関する上記説明は、排ガス浄化用触媒１Ｂにも適用される。 <Second embodiment>
An exhaust gas purifying catalyst 1B according to a second embodiment of the present invention will be described below with reference to FIG. In the exhaust gas purifying catalyst 1B, the same members as those of the exhaust gas purifying catalyst 1A are denoted by the same reference numerals as those of the exhaust gas purifying catalyst 1A. Unless otherwise stated below, the above description of the exhaust gas purifying catalyst 1A also applies to the exhaust gas purifying catalyst 1B.
　図５に示すように、排ガス浄化用触媒１Ｂは、
　基材１０に、一部のセル１３の排ガス流出側の端部を封止する第１封止部１４、及び、残りのセル１３の排ガス流入側の端部を封止する第２封止部１５が設けられており、これにより、基材１０に、排ガス流入側の端部が開口しており、排ガス流出側の端部が第１封止部１４で閉塞されている流入側セル１３ａ、及び、排ガス流入側の端部が第２封止部１５で閉塞されており、排ガス流出側の端部が開口している流出側セル１３ｂが形成されている点、並びに、
　基材１０の隔壁部１２の流入側セル１３ａ側に触媒層２０ａが設けられており、基材１０の隔壁部１２の流出側セル１３ｂ側に触媒層２０ｂが設けられている点
で、排ガス浄化用触媒１Ａと相違する。 As shown in FIG. 5, the exhaust gas purifying catalyst 1B is
In the base material 10, a first sealing portion 14 that seals the ends of some of the cells 13 on the exhaust gas outflow side, and a second sealing portion that seals the ends of the remaining cells 13 on the exhaust gas inflow side. 15 is provided, whereby the inflow-side cell 13a is open at the end on the exhaust gas inflow side and the end on the exhaust gas outflow side is closed with the first sealing portion 14 in the base material 10; And, the end on the exhaust gas inflow side is closed by the second sealing portion 15, and the outflow side cell 13b is formed in which the end on the exhaust gas outflow side is open;
The catalyst layer 20a is provided on the inflow side cell 13a side of the partition wall portion 12 of the base material 10, and the catalyst layer 20b is provided on the outflow side cell 13b side of the partition wall portion 12 of the base material 10. It is different from the catalyst for catalyst 1A.
　図５に示すように、１個の流入側セル１３ａの周りには、複数（例えば４つ）の流出側セル１３ｂが隣接するように配置されており、流入側セル１３ａと、当該流入側セル１３ａに隣接する流出側セル１３ｂとは、多孔質の隔壁部１２によって仕切られている。 As shown in FIG. 5, a plurality of (for example, four) outflow-side cells 13b are arranged adjacently around one inflow-side cell 13a. The outflow side cell 13b adjacent to 13a is separated by a porous partition wall portion 12 .
　図５に示すように、触媒層２０ａは、隔壁部１２の排ガス流出側の端部に至らないように、隔壁部１２の排ガス流入側の端部から排ガス流通方向Ｘに沿って延在している。触媒層２０ａは、隔壁部１２の排ガス流入側の端部から隔壁部１２の排ガス流出側の端部まで延在していてもよい。 As shown in FIG. 5, the catalyst layer 20a extends along the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas inflow side so as not to reach the exhaust gas outflow end of the partition wall 12. there is The catalyst layer 20 a may extend from the end of the partition wall 12 on the exhaust gas inflow side to the end of the partition wall 12 on the exhaust gas outflow side.
　図５に示すように、触媒層２０ｂは、隔壁部１２の排ガス流入側の端部に至らないように、隔壁部１２の排ガス流出側の端部から排ガス流通方向Ｘとは反対の方向に沿って延在している。触媒層２０ｂは、隔壁部１２の排ガス流出側の端部から隔壁部１２の排ガス流入側の端部まで延在していてもよい。 As shown in FIG. 5, the catalyst layer 20b is formed along the direction opposite to the exhaust gas flow direction X from the end of the partition wall 12 on the exhaust gas outflow side so as not to reach the end of the partition wall 12 on the exhaust gas inflow side. extended. The catalyst layer 20b may extend from the end of the partition wall 12 on the exhaust gas outflow side to the end of the partition wall 12 on the exhaust gas inflow side.
　触媒層２０ａ及び２０ｂの少なくとも一方は、Ｃｅ系酸化物粒子と、Ｃｅ－Ｚｒ系複合酸化物粒子と、貴金属元素とを含む本発明の触媒層であり、本発明の触媒層に関する上記説明が適用される。触媒層２０ａ及び２０ｂの組成等は同一であってもよいし、異なっていてもよい。 At least one of the catalyst layers 20a and 20b is the catalyst layer of the present invention containing Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element, and the above description of the catalyst layer of the present invention applies. be done. The composition and the like of the catalyst layers 20a and 20b may be the same or different.
　排ガス浄化用触媒１Ｂでは、流入側セル１３ａの排ガス流入側の端部（開口部）から流入した排ガスが、多孔質の隔壁部１２を通過して流出側セル１３ｂの排ガス流出側の端部（開口部）から流出する。このような様式は、ウォールフロー型と呼ばれる。 In the exhaust gas purifying catalyst 1B, the exhaust gas that has flowed in from the end (opening) of the inflow-side cell 13a on the exhaust gas inflow side passes through the porous partition wall portion 12 and reaches the end (opening) of the outflow-side cell 13b on the exhaust gas outflow side. opening). Such a mode is called a wall-flow type.
　排ガス浄化用触媒１Ｂにおいて、流入側セル１３ａの排ガス流入側の端部（開口部）から流入した排ガスが、多孔質の隔壁部１２を通過する際、排ガス中の粒子状物質（ＰＭ：Ｐａｒｔｉｃｕｌａｔｅ　Ｍａｔｔｅｒ）が、隔壁部１２の細孔に捕集される。したがって、排ガス浄化用触媒１Ｂは、ガソリンエンジン用のパティキュレートフィルタ（Ｇａｓｏｌｉｎｅ　Ｐａｒｔｉｃｕｌａｔｅ　Ｆｉｌｔｅｒ）又はディーゼルエンジン用のパティキュレートフィルタ（Ｄｉｅｓｅｌ　Ｐａｒｔｉｃｕｌａｔｅ　Ｆｉｌｔｅｒ）として有用である。 In the exhaust gas purifying catalyst 1B, when the exhaust gas that has flowed in from the exhaust gas inflow side end (opening) of the inflow-side cell 13a passes through the porous partition wall portion 12, particulate matter (PM) in the exhaust gas ) are collected in the pores of the partition wall portion 12 . Therefore, the exhaust gas purifying catalyst 1B is useful as a particulate filter for gasoline engines or a diesel particulate filter for diesel engines.
　排ガス浄化用触媒１Ｂは、以下の方法により製造することができる。基材１０の排ガス流入側の端部を、触媒層２０ａを形成するためのスラリー中に浸漬し、反対側からスラリーを吸引し、乾燥させ、触媒層２０ａの前駆層を形成する。基材１０の排ガス流出側の端部を、触媒層２０ｂを形成するためのスラリー中に浸漬し、反対側からスラリーを吸引し、乾燥させ、触媒層２０ｂの前駆層を形成する。触媒層２０ａの前駆層及び触媒層２０ｂの前駆層を形成した後、焼成することにより、触媒層２０ａ及び触媒層２０ｂが形成され、排ガス浄化用触媒１Ｂが製造される。排ガス浄化用触媒１Ｂの製造条件等は、排ガス浄化用触媒１Ａと同様である。 The exhaust gas purifying catalyst 1B can be manufactured by the following method. The end of the substrate 10 on the exhaust gas inflow side is immersed in the slurry for forming the catalyst layer 20a, and the slurry is sucked from the opposite side and dried to form a precursor layer of the catalyst layer 20a. The end of the substrate 10 on the exhaust gas outflow side is immersed in the slurry for forming the catalyst layer 20b, and the slurry is sucked from the opposite side and dried to form a precursor layer of the catalyst layer 20b. After forming a precursor layer of the catalyst layer 20a and a precursor layer of the catalyst layer 20b, they are fired to form the catalyst layer 20a and the catalyst layer 20b, thereby manufacturing the exhaust gas purifying catalyst 1B. The manufacturing conditions and the like of the exhaust gas purifying catalyst 1B are the same as those of the exhaust gas purifying catalyst 1A.
　以下、実施例、比較例及び試験例に基づいて、本発明をさらに詳述する。 The present invention will be described in further detail below based on Examples, Comparative Examples and Test Examples.
　酸化セリウム粉末を準備し、以下の実施例、比較例及び比較例で使用した。酸化セリウム粉末におけるＣｅのＣｅＯ２換算量はほぼ１００質量％（＞９９質量％）であった。 A cerium oxide powder was prepared and used in the following examples, comparative examples and comparative examples. The CeO2 equivalent amount of Ce in the cerium oxide powder was nearly 100 wt% (>99 wt%).
〔実施例１〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液（ＡｌのＡｌ２Ｏ３換算量：５．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９５．０ｇ）を添加し、室温で２時間攪拌した後、蒸発乾固して乾燥粉末を得た。得られた乾燥粉末を大気中１０００℃で１時間焼成し、実施例１のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＡｌのＡｌ２Ｏ３換算量：５．０質量％）を得た。 [Example 1]
(1) Preparation of Ce - based oxide Cerium oxide powder (CeO2 equivalent amount: 95.0 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 5.0 g), and the mixture was left at room temperature for 2 hours. After stirring, it was evaporated to dryness to obtain a dry powder. The resulting dry powder was calcined in the air at 1000° C. for 1 hour, and the Ce-based oxide powder of Example 1 (amount of Ce converted to CeO2 : 95.0% by mass , amount of Al converted to Al2O3 : 5.0% by mass) was obtained. 0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　触媒組成物１００質量部を作製するために、ジニトロジアンミン白金硝酸水溶液（Ｐｔの金属換算量：１．０質量部）に、Ｃｅ－Ｚｒ系複合酸化物粉末（ＣｅのＣｅＯ２換算量：４０質量％、ＺｒのＺｒＯ２換算量：５０質量％、ＬａのＬａ２Ｏ３換算量：１０質量％）　６１．０質量部、Ａｌ系酸化物粉末（ＡｌのＡｌ２Ｏ３換算量：９９質量％、ＬａのＬａ２Ｏ３換算量：１質量％）　２８．０質量部、及び実施例１のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＡｌのＡｌ２Ｏ３換算量：５．０質量％）　１０．０質量部を順次添加し、１時間静置してジニトロジアンミン白金硝酸水溶液をＣｅ－Ｚｒ系複合酸化物粉末、Ａｌ系酸化物粉末及びＣｅ系酸化物粉末に含浸及び担持させた後、蒸発乾固して乾燥粉末を得た。得られた乾燥粉末を大気雰囲気下、５００℃で１時間焼成し、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purifying Catalyst Composition In order to prepare 100 parts by mass of the catalyst composition, a Ce—Zr-based composite oxide Powder ( CeO2 conversion amount: 40 mass%, Zr ZrO2 conversion amount: 50 mass% , La conversion amount of La2O3: 10 mass%) 61.0 parts by mass, Al - based oxide powder (Al of Al 2 O 3 equivalent: 99% by mass, La equivalent of La 2 O 3 : 1% by mass) 28.0 parts by mass, and the Ce-based oxide powder of Example 1 (CeO 2 equivalent amount of Ce: 95 0% by mass, the amount of Al converted to Al 2 O 3 : 5.0% by mass) 10.0 parts by mass were sequentially added and allowed to stand for 1 hour to form an aqueous solution of dinitrodiammineplatinum nitric acid into a Ce—Zr-based composite oxide powder. , Al-based oxide powder and Ce-based oxide powder, and then evaporated to dryness to obtain dry powder. The obtained dry powder was calcined at 500° C. for 1 hour in an air atmosphere to obtain a powdery catalyst composition.
　得られた触媒組成物を電子プローブマイクロアナライザー（ＥＰＭＡ）で分析したところ、ＣｅＯ２と同じ位置に存在するＡｌ２Ｏ３が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＡｌを含む酸化物で構成されていることが確認された。 Electron probe microanalyzer (EPMA) analysis of the resulting catalyst composition detected Al 2 O 3 co-located with CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Al.
〔実施例２〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸マグネシウム水溶液（ＭｇのＭｇＯ換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、実施例２のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＭｇのＭｇＯ換算量：５．０質量％）を得た。 [Example 2]
(1) Preparation of Ce-based oxide Ce of Example 2 was prepared in the same manner as in Example 1, except that an aqueous magnesium nitrate solution (Mg in terms of MgO: 5.0 g) was used instead of the aqueous aluminum nitrate solution. A system oxide powder ( amount of Ce converted to CeO2: 95.0% by mass, amount of Mg converted to MgO: 5.0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、実施例２のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Production of Exhaust Gas Purifying Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1 except that the Ce-based oxide powder of Example 2 was used instead of the Ce-based oxide powder of Example 1 was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＭｇＯが検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＭｇを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected MgO co - located with CeO2. As a result, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Mg.
〔実施例３〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、実施例３のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＬａのＬａ２Ｏ３換算量：５．０質量％）を得た。 [Example 3]
(1) Preparation of Ce-based Oxide In the same manner as in Example 1, except that an aqueous lanthanum nitrate solution (La converted to La 2 O 3 : 5.0 g) was used instead of the aqueous aluminum nitrate solution. 3 (amount of Ce converted to CeO2: 95.0% by mass , amount of La converted to La2O3 : 5.0% by mass).
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、実施例３のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purification Catalyst Composition In the same manner as in Example 1, except that the Ce-based oxide powder of Example 3 was used instead of the Ce-based oxide powder of Example 1, powdery was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＬａ２Ｏ３が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＬａを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected La 2 O 3 co-located with CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and La.
〔実施例４〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸プラセオジム水溶液（ＰｒのＰｒ６Ｏ１１換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、実施例４のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＰｒのＰｒ６Ｏ１１換算量：５．０質量％）を得た。 [Example 4]
(1) Preparation of Ce-based Oxide The procedure of Example 1 was repeated except that an aqueous solution of praseodymium nitrate (5.0 g of Pr in terms of Pr 6 O 11 ) was used instead of the aqueous solution of aluminum nitrate. 4 (amount of Ce converted to CeO2: 95.0% by mass, amount of Pr converted to Pr6O11 : 5.0% by mass).
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、実施例４のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purification Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1, except that the Ce-based oxide powder of Example 4 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＰｒ６Ｏ１１が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＰｒを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected Pr 6 O 11 co-located with CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Pr.
〔実施例５〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸イットリウム水溶液（ＹのＹ２Ｏ３換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、実施例５のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＹのＹ２Ｏ３換算量：５．０質量％）を得た。 [Example 5]
(1) Production of Ce-based Oxide The procedure of Example 1 was repeated except that an aqueous solution of yttrium nitrate (Y 2 O 3 equivalent: 5.0 g) was used instead of the aqueous solution of aluminum nitrate. A Ce - based oxide powder No. 5 (amount of Ce converted to CeO2: 95.0% by mass, amount of Y converted to Y2O3: 5.0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、実施例５のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purifying Catalyst Composition A powdery catalyst composition was produced in the same manner as in Example 1, except that the Ce-based oxide powder of Example 5 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＹ２Ｏ３が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＹを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected Y 2 O 3 present at the same position as CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of an oxide containing Ce and Y.
〔実施例６〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸ネオジム水溶液（ＮｄのＮｄ２Ｏ３換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、実施例６のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＮｄのＮｄ２Ｏ３換算量：５．０質量％）を得た。 [Example 6]
(1) Preparation of Ce-based oxide The procedure of Example 1 was repeated except that an aqueous solution of neodymium nitrate (Nd converted to Nd 2 O 3 : 5.0 g) was used instead of the aqueous solution of aluminum nitrate. No. 6 Ce - based oxide powder (amount of Ce converted to CeO2: 95.0% by mass , amount of Nd converted to Nd2O3 : 5.0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、実施例６のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purification Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1 except that the Ce-based oxide powder of Example 6 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＮｄ２Ｏ３が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＮｄを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected Nd 2 O 3 co-located with CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Nd.
〔比較例１〕
　触媒組成物１００質量を作製するために、ジニトロジアンミン白金硝酸水溶液（Ｐｔの金属換算量：１．０質量部）に、Ｃｅ－Ｚｒ系複合酸化物粉末（ＣｅのＣｅＯ２換算量：４０質量％、ＺｒのＺｒＯ２換算量：５０質量％、ＬａのＬａ２Ｏ３換算量：１０質量％）　６６．０質量部、及びＡｌ系酸化物粉末（ＡｌのＡｌ２Ｏ３換算量：９９質量％、ＬａのＬａ２Ｏ３換算量：１質量％）　３３．０質量部を順次添加し、１時間静置してジニトロジアンミン白金硝酸水溶液をＣｅ－Ｚｒ系複合酸化物粉末及びＡｌ系酸化物粉末に含浸及び担持させた後、蒸発乾固して乾燥粉末を得た。得られた乾燥粉末を大気雰囲気下、５００℃で１時間焼成し、粉末状の触媒組成物を得た。 [Comparative Example 1]
In order to prepare 100 mass of the catalyst composition, an aqueous solution of dinitrodiammineplatinum nitrate (amount of Pt in terms of metal: 1.0 parts by mass) was added with Ce—Zr-based composite oxide powder (amount of Ce in terms of CeO 2 : 40% by mass. , Zr in terms of ZrO 2 : 50% by mass, La in terms of La 2 O 3 : 10% by mass) 66.0 parts by mass, and Al-based oxide powder (Al in terms of Al 2 O 3 : 99% by mass , La converted amount of La 2 O 3 : 1% by mass) 33.0 parts by mass were sequentially added and allowed to stand for 1 hour to form a dinitrodiammineplatinum nitric acid aqueous solution into a Ce—Zr-based composite oxide powder and an Al-based oxide powder. After being impregnated with and supported on, it was evaporated to dryness to obtain a dry powder. The obtained dry powder was calcined at 500° C. for 1 hour in an air atmosphere to obtain a powdery catalyst composition.
〔比較例２〕
　触媒組成物１００質量を作製するために、ジニトロジアンミン白金硝酸水溶液（Ｐｔの金属換算量：１．０質量部）に、Ｃｅ－Ｚｒ系複合酸化物粉末（ＣｅのＣｅＯ２換算量：４０質量％、ＺｒのＺｒＯ２換算量：５０質量％、ＬａのＬａ２Ｏ３換算量：１０質量％）　６１．０質量部、Ａｌ系酸化物粉末（ＡｌのＡｌ２Ｏ３換算量：９９質量％、ＬａのＬａ２Ｏ３換算量：１質量％）　２８．０質量部、及び酸化セリウム粉末（ＣｅのＣｅＯ２換算量：ほぼ１００質量％（＞９９質量％））　１０．０質量部を順次添加し、１時間静置してジニトロジアンミン白金硝酸水溶液をＣｅ－Ｚｒ系複合酸化物粉末、Ａｌ系酸化物粉末及び酸化セリウム粉末に含浸及び担持させた後、蒸発乾固して乾燥粉末を得た。得られた乾燥粉末を大気雰囲気下、５００℃で１時間焼成し、粉末状の触媒組成物を得た。 [Comparative Example 2]
In order to prepare 100 mass of the catalyst composition, an aqueous solution of dinitrodiammineplatinum nitrate (amount of Pt in terms of metal: 1.0 parts by mass) was added with Ce—Zr-based composite oxide powder (amount of Ce in terms of CeO 2 : 40% by mass. , Zr converted to ZrO2: 50% by mass, La converted to La2O3: 10 % by mass) 61.0 parts by mass, Al - based oxide powder ( Al converted to Al2O3 : 99% by mass , 28.0 parts by mass of La equivalent to La 2 O 3 : 1% by mass) and 10.0 parts by mass of cerium oxide powder (CeO 2 equivalent amount of Ce: approximately 100% by mass (>99% by mass)) are sequentially added. Then, the dinitrodiammineplatinum nitric acid aqueous solution was allowed to stand for 1 hour to impregnate and support the Ce—Zr-based composite oxide powder, the Al-based oxide powder, and the cerium oxide powder, and then evaporated to dryness to obtain a dry powder. . The obtained dry powder was calcined at 500° C. for 1 hour in an air atmosphere to obtain a powdery catalyst composition.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＡｌ２Ｏ３はほとんど検出されなかった。 When the resulting catalyst composition was analyzed by EPMA, almost no Al 2 O 3 co-located with CeO 2 was detected.
〔比較例３〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸ジルコニウム水溶液（ＺｒのＺｒＯ２換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、比較例３のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＺｒのＺｒＯ２換算量：５．０質量％）を得た。 [Comparative Example 3]
(1) Preparation of Ce-based oxide Comparative Example 3 was prepared in the same manner as in Example 1, except that an aqueous zirconium nitrate solution ( Zr converted to ZrO2: 5.0 g) was used instead of the aqueous aluminum nitrate solution. A Ce - based oxide powder ( amount of Ce converted to CeO2: 95.0% by mass, amount of Zr converted to ZrO2: 5.0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、比較例３のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purifying Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1, except that the Ce-based oxide powder of Comparative Example 3 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＺｒＯ２が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＺｒを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected ZrO 2 co-located with CeO 2 . As a result, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Zr.
〔比較例４〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、リン酸水溶液（ＰのＰ４Ｏ１０換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、比較例４のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＰのＰ４Ｏ１０換算量：５．０質量％）を得た。 [Comparative Example 4]
(1) Preparation of Ce-based oxide A comparative example was prepared in the same manner as in Example 1, except that an aqueous solution of phosphoric acid (P converted to P 4 O 10 : 5.0 g) was used instead of the aqueous solution of aluminum nitrate. 4 (amount of Ce converted to CeO2 : 95.0% by mass, amount of P converted to P4O10 : 5.0% by mass).
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、比較例４のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Production of Exhaust Gas Purification Catalyst Composition A powdery catalyst composition was produced in the same manner as in Example 1, except that the Ce-based oxide powder of Comparative Example 4 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＰ４Ｏ１０が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＰを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected P 4 O 10 present at the same position as CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of an oxide containing Ce and P.
〔比較例５〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸スズ水溶液（ＳｎのＳｎＯ換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、比較例５のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＳｎのＳｎＯ換算量：５．０質量％）を得た。 [Comparative Example 5]
(1) Preparation of Ce-based oxide Ce of Comparative Example 5 was prepared in the same manner as in Example 1, except that an aqueous tin nitrate solution (Sn converted to SnO: 5.0 g) was used instead of the aqueous aluminum nitrate solution. A system oxide powder ( amount of Ce converted to CeO2: 95.0% by mass, amount of Sn converted to SnO: 5.0% by mass) was obtained.
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、比較例５のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purifying Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1, except that the Ce-based oxide powder of Comparative Example 5 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＳｎＯが検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＳｎを含む酸化物で構成されていることが確認された。 EPMA analysis of the resulting catalyst composition detected SnO co - located with CeO2. As a result, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and Sn.
〔比較例６〕
（１）Ｃｅ系酸化物の作製
　硝酸アルミニウム水溶液に代えて、硝酸インジウム水溶液（ＩｎのＩｎ２Ｏ３換算量：５．０ｇ）を使用した点を除き、実施例１と同様にして、比較例６のＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＩｎのＩｎ２Ｏ３換算量：５．０質量％）を得た。 [Comparative Example 6]
(1) Preparation of Ce-based oxide A comparative example was prepared in the same manner as in Example 1, except that an aqueous indium nitrate solution ( in terms of In2O3 of In : 5.0 g) was used instead of the aqueous aluminum nitrate solution. 6 (amount of Ce converted to CeO2: 95.0% by mass , amount of In converted to In2O3: 5.0% by mass).
（２）排ガス浄化用触媒組成物の作製
　実施例１のＣｅ系酸化物粉末に代えて、比較例６のＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 (2) Preparation of Exhaust Gas Purifying Catalyst Composition A powdery catalyst composition was prepared in the same manner as in Example 1, except that the Ce-based oxide powder of Comparative Example 6 was used instead of the Ce-based oxide powder of Example 1. was obtained.
　得られた触媒組成物をＥＰＭＡで分析したところ、ＣｅＯ２と同じ位置に存在するＩｎ２Ｏ３が検出された。これにより、触媒組成物に含まれるＣｅ系酸化物粒子が、Ｃｅ及びＩｎを含む酸化物で構成されていることが確認された。 EPMA analysis of the obtained catalyst composition detected In 2 O 3 present at the same position as CeO 2 . From this, it was confirmed that the Ce-based oxide particles contained in the catalyst composition were composed of oxides containing Ce and In.
〔試験例１〕
（１）Ｃｅ系酸化物粉末の平均粒子径の測定
　実施例１～６及び比較例１～６で得られた各Ｃｅ系酸化物粉末の平均粒子径を次の通り測定した。走査型電子顕微鏡（ＪＥＯＬ製　ＪＣＭ－７０００）を使用して、Ｃｅ系酸化物粉末を観察し、視野内から任意に選択された１００個の粒子の定方向径（フェレ径）を測定し、平均値をＣｅ系酸化物粉末の平均粒子径とした。 [Test Example 1]
(1) Measurement of Average Particle Size of Ce-Based Oxide Powder The average particle size of each Ce-based oxide powder obtained in Examples 1-6 and Comparative Examples 1-6 was measured as follows. Observe the Ce-based oxide powder using a scanning electron microscope (JCM-7000 manufactured by JEOL), measure the unidirectional diameter (Ferret diameter) of 100 particles arbitrarily selected from within the field of view, and average The value was taken as the average particle size of the Ce-based oxide powder.
（２）Ｃｅ系酸化物粉末を使用した結晶子径の測定
　実施例１～６及び比較例１～６で得られた各Ｃｅ系酸化物粉末を使用して、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径を次の通り測定した。Ｃｅ系酸化物粉末及び市販の粉末Ｘ線回折装置（株式会社リガク社製「ＭｉｎｉＦｌｅｘ６００」）を使用して、Ｘ線源：ＣｕＫα、操作軸：２θ／θ、測定方法：連続、計数単位：ｃｐｓ、開始角度：５°、終了角度：９０°、サンプリング幅：０．０２°、スキャンスピード：１０°／分、電圧：４０ｋＶ、電流：１５０ｍＡの条件でＸ線回折（ＸＲＤ）を行った。得られたＸＲＤパターンにおいて、ＣｅＯ２に由来する回折ピークのうち、２θ＝５５～５８°に存在するピーク及び２θ＝４６～４９°に存在するピークを特定し、解析ソフト（株式会社リガク社製「ＰＤＸＬ　ｖｅｒｓｉｏｎ　２」）を使用して、特定したピークにシェラーの式を適用し、結晶子径を自動算出した。２θ＝５５～５８°に存在するピークから求めた結晶子径と、２θ＝４６～４９°に存在するピークから求めた結晶子径とを比較し、大きい方の結晶子径を、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径として選択した。 (2) Measurement of crystallite size using Ce-based oxide powder Using each Ce-based oxide powder obtained in Examples 1-6 and Comparative Examples 1-6, CeO 2 The crystallite size of was measured as follows. Using Ce-based oxide powder and a commercially available powder X-ray diffractometer ("MiniFlex 600" manufactured by Rigaku Co., Ltd.), X-ray source: CuKα, operating axis: 2θ/θ, measuring method: continuous, counting unit: cps , start angle: 5°, end angle: 90°, sampling width: 0.02°, scan speed: 10°/min, voltage: 40 kV, current: 150 mA. In the obtained XRD pattern, among the diffraction peaks derived from CeO 2 , peaks present at 2θ = 55 to 58° and peaks present at 2θ = 46 to 49° were identified and analyzed with analysis software (manufactured by Rigaku Corporation). "PDXL version 2") was used to automatically calculate the crystallite size by applying the Scherrer equation to the identified peaks. The crystallite diameter obtained from the peak present at 2θ = 55 to 58° and the crystallite diameter obtained from the peak present at 2θ = 46 to 49° were compared, and the larger crystallite diameter was obtained by Ce-based oxidation. was selected as the crystallite size of CeO2 in the solid particles.
（３）触媒組成物を使用した結晶子径の測定
　実施例１～６及び比較例１～６で得られた各触媒組成物を使用して、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径を上記（２）と同様にして測定した。 ( 3 ) Measurement of crystallite size using catalyst composition was measured in the same manner as in (2) above.
（４）貴金属分散度の測定
　石英製の管状炉を使用して、Ｏ２ガス　０．５ｖｏｌ．％、水蒸気としてＨ２Ｏ　１０ｖｏｌ．％，バランスガスとしてＮ２を流通させた雰囲気下、１０００℃で２０時間、実施例１～６及び比較例１～６で得られた各触媒組成物に熱処理を施した。熱処理後の触媒組成物を、金属分散度測定装置（マイクロトラック・ベル株式会社製　ＢＥＬＭＥＴＡＬ３）を使用して、ＣＯパルス法により、貴金属へのＣＯ吸着量を測定し、貴金属分散度を算出した。ここで、貴金属分散度とは、触媒組成物中の貴金属原子（実施例１～６及び比較例１～６ではＰｔ）の総数Ａに対する、貴金属粒子表面に露出している貴金属原子の数Ｂの比率であり、貴金属分散度（％）＝（Ｂ／Ａ）×１００により算出される。貴金属粒子表面に露出している貴金属原子の数Ｂは、貴金属粒子表面に露出している貴金属原子とＣＯとが１：１で吸着するという前提に基づき、ＣＯパルス法により測定されたＣＯ吸着量から算出される。 (4) Measurement of Noble Metal Dispersion Using a quartz tubular furnace, 0.5 vol . %, H 2 O 10 vol. Each catalyst composition obtained in Examples 1 to 6 and Comparative Examples 1 to 6 was heat-treated at 1000° C. for 20 hours in an atmosphere in which N 2 was passed as a balance gas. After the heat treatment, the amount of CO adsorbed on the noble metal was measured by the CO pulse method using a metal dispersion measuring device (BELMETAL3 manufactured by Microtrack Bell Co., Ltd.), and the noble metal dispersion was calculated. Here, the degree of dispersion of noble metals means the ratio of the number B of noble metal atoms exposed on the surface of the noble metal particles to the total number A of noble metal atoms (Pt in Examples 1 to 6 and Comparative Examples 1 to 6) in the catalyst composition. It is a ratio, and is calculated by noble metal dispersity (%)=(B/A)×100. The number B of noble metal atoms exposed on the noble metal particle surface is the amount of CO adsorption measured by the CO pulse method, based on the premise that the noble metal atoms exposed on the noble metal particle surface and CO adsorb at a ratio of 1:1. calculated from
（５）ＯＳＣ量の測定
　金属分散度測定装置（マイクロトラック・ベル株式会社製　ＢＥＬＭＥＴＡＬ３）を使用して、実施例１～６及び比較例１～６で得られた各触媒組成物のＯＳＣ測定をＣＯパルス法により行った。 (5) Measurement of OSC amount The OSC of each catalyst composition obtained in Examples 1 to 6 and Comparative Examples 1 to 6 was measured using a metal dispersion measuring device (BELMETAL3 manufactured by Microtrack Bell Co., Ltd.). It was carried out by the CO pulse method.
　ＯＳＣ測定では、Ｈｅ流通下、触媒組成物を８００℃に昇温し、４０分間、当該温度に保持する前処理を行った後、３００℃まで降温した。次いで、触媒組成物を３００℃に保持した状態で、Ｏ２ガスを４パルスに分けて注入し、酸化処理を行った後、ＣＯを含む試験ガスを１０パルスに分けて注入し、消費されたＣＯガス総量から、触媒組成物の単位重量当たりのＯＳＣ量（μｍｏｌ／ｇ）を、金属分散度測定装置（マイクロトラック・ベル株式会社製　ＢＥＬＭＥＴＡＬ３）に内蔵されている熱伝導度型検出器（ＴＣＤ）で測定した。 In the OSC measurement, the temperature of the catalyst composition was raised to 800°C under the flow of He, and the temperature was lowered to 300°C after a pretreatment of holding at that temperature for 40 minutes. Then, while the catalyst composition was kept at 300 ° C., O gas was injected in 4 pulses and subjected to oxidation treatment, and then a test gas containing CO was injected in 10 pulses and consumed. A thermal conductivity detector (TCD ).
（６）排ガス浄化性能の評価
　石英製の管状炉を使用して、Ｏ２ガス　０．５ｖｏｌ．％、水蒸気としてＨ２Ｏ　１０ｖｏｌ．％、バランスガスとしてＮ２を流通させた雰囲気下、１０００℃で３０時間、実施例１～６及び比較例１～６で得られた各触媒組成物に熱処理を施した。熱処理後の触媒組成物を反応管に充填し、固定床流通型反応装置を使用して、熱処理後の触媒組成物の排ガス浄化性能を測定した。具体的には、熱処理後の触媒組成物０．１ｇを反応管に充填し、模擬排ガス（ＣＯ：３０００ｐｐｍ、Ｃ３Ｈ６：１０００ｐｐｍＣ、ＮＯ：５００ｐｐｍ、Ｏ２：０．２８％、ＣＯ２：１４％、Ｈ２Ｏ：１０％、Ｎ２：残部）を、昇温速度：１０℃／分、空燃比（Ａ／Ｆ）：１４．６、総流量：１０００ｍＬ／分の条件で反応管に導入した。なお、「Ａ／Ｆ」は、Ａｉｒ／Ｆｕｅｌの略で、空気と燃料との比率を示す数値である。昇温速度１０℃／分で６００℃まで昇温させた後、１０分間保持し、前処理を行った。次いで、一旦冷却した後、１００℃から６００℃まで昇温速度１０℃／分で昇温させ、反応管の出口から流出する模擬排ガスに含まれるＮＯ量をフーリエ変換赤外分光法（ＦＴ－ＩＲ）により測定し、下記式に基づいて浄化率を求めた。なお、下記式中、Ｘは、触媒組成物未設置のときの検出量を表し、Ｙは、触媒組成物設置時の検出量を表す。
　浄化率（％）＝（Ｘ－Ｙ）／Ｘ×１００ ( 6 ) Evaluation of Exhaust Gas Purification Performance Using a tubular furnace made of quartz, 0.5 vol. %, H 2 O 10 vol. %, under an atmosphere in which N 2 was circulated as a balance gas, the catalyst compositions obtained in Examples 1 to 6 and Comparative Examples 1 to 6 were heat-treated at 1000° C. for 30 hours. The catalyst composition after the heat treatment was packed in a reaction tube, and the exhaust gas purification performance of the catalyst composition after the heat treatment was measured using a fixed bed flow reactor. Specifically, 0.1 g of the catalyst composition after heat treatment was filled in a reaction tube, and simulated exhaust gas (CO: 3000 ppm, C 3 H 6 : 1000 ppmC, NO: 500 ppm, O 2 : 0.28%, CO 2 : 14%, H 2 O: 10%, N 2 : balance) into the reaction tube under the conditions of a temperature increase rate of 10°C/min, an air-fuel ratio (A/F) of 14.6, and a total flow rate of 1000 mL/min. introduced. Note that "A/F" is an abbreviation for Air/Fuel, and is a numerical value indicating the ratio of air to fuel. After the temperature was raised to 600° C. at a temperature elevation rate of 10° C./min, it was held for 10 minutes to perform pretreatment. Then, after cooling once, the temperature is raised from 100 ° C. to 600 ° C. at a temperature increase rate of 10 ° C./min, and the amount of NO contained in the simulated exhaust gas flowing out from the outlet of the reaction tube is measured by Fourier transform infrared spectroscopy (FT-IR). ), and the purification rate was determined based on the following formula. In the following formula, X represents the amount detected when the catalyst composition was not installed, and Y represents the amount detected when the catalyst composition was installed.
Purification rate (%) = (XY)/X x 100
　ＮＯの浄化率が５０％に達したときの、反応管の入口におけるガス温度をライトオフ温度Ｔ５０（℃）として求めた。なお、ライトオフ温度Ｔ５０は、昇温時について求めた。 The gas temperature at the inlet of the reaction tube when the NO purification rate reached 50% was obtained as the light-off temperature T50 (°C). Note that the light-off temperature T50 was obtained when the temperature was raised.
　Ｃｅ系酸化物粉末の平均粒子径及びＣｅ系酸化物粉末を使用して測定したＣｅＯ２の結晶子径の測定結果を表１に示す。触媒組成物を使用して測定したＣｅＯ２の結晶子径、貴金属分散度、ＯＳＣ量及びＴ５０の測定結果を表２に示す。表１には、実施例１～６及び比較例１～６において触媒組成物の材料として使用したＣｅ系酸化物粉末の組成及び添加量も示す。表１中、「ＣｅＯ２」はＣｅのＣｅＯ２換算量（質量％）を、「Ａｌ２Ｏ３」はＡｌのＡｌ２Ｏ３換算量（質量％）を、「ＭｇＯ」はＭｇのＭｇＯ換算量（質量％）、「Ｌａ２Ｏ３」はＬａのＬａ２Ｏ３換算量（質量％）を、「Ｐｒ６Ｏ１１」はＰｒのＰｒ６Ｏ１１換算量（質量％）、「Ｙ２Ｏ３」はＹのＹ２Ｏ３換算量（質量％）、「Ｎｄ２Ｏ３」はＮｄのＮｄ２Ｏ３換算量（質量％）、「ＺｒＯ２」はＺｒのＺｒＯ２換算量を、「Ｐ４Ｏ１０」はＰのＰ４Ｏ１０換算量（質量％）を、「ＳｎＯ」はＳｎのＳｎＯ換算量（質量％）を、「Ｉｎ２Ｏ３」はＩｎのＩｎ２Ｏ３換算量（質量％）を表す。 Table 1 shows the average particle size of the Ce-based oxide powder and the crystallite size of CeO 2 measured using the Ce-based oxide powder. Table 2 shows the measurement results of CeO 2 crystallite size, noble metal dispersity, OSC content and T50 measured using the catalyst composition. Table 1 also shows the composition and addition amount of the Ce-based oxide powder used as the material of the catalyst composition in Examples 1-6 and Comparative Examples 1-6. In Table 1, “CeO 2 ” is the amount of Ce converted to CeO 2 (% by mass), “Al 2 O 3 ” is the amount of Al converted to Al 2 O 3 (% by mass), and “MgO” is the amount of Mg converted to MgO. amount (% by mass), "La 2 O 3 " is the amount of La converted to La 2 O 3 (% by mass), "Pr 6 O 11 " is the amount of Pr converted to Pr 6 O 11 (% by mass), "Y 2 “O 3 ” is the amount of Y converted to Y 2 O 3 (% by mass), “Nd 2 O 3 ” is the amount of Nd converted to Nd 2 O 3 (% by mass), and “ZrO 2 ” is the amount of Zr converted to ZrO 2 , “P 4 O 10 ” is the amount of P converted to P 4 O 10 (% by mass), “SnO” is the amount of Sn converted to SnO (% by mass), and “In 2 O 3 ” is the amount of In converted to In 2 O 3 It represents the amount (% by mass).
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000001
Figure JPOXMLDOC01-appb-T000002
Figure JPOXMLDOC01-appb-T000002
　表２に示されるように、実施例１～６の触媒組成物のＴ５０は比較例１～６の触媒組成物のＴ５０よりもよりも低く、実施例１～６の触媒組成物の排ガス浄化性能は比較例１～６の触媒組成物の排ガス浄化性能よりも向上していた。 As shown in Table 2, the T50 of the catalyst compositions of Examples 1-6 is lower than the T50 of the catalyst compositions of Comparative Examples 1-6, and the exhaust gas purification performance of the catalyst compositions of Examples 1-6 was better than the exhaust gas purification performance of the catalyst compositions of Comparative Examples 1-6.
　表２に示されるように、実施例１及び２の触媒組成物の貴金属分散度は実施例３～６の触媒組成物の貴金属分散度よりも高い一方、実施例３～６の触媒組成物のＯＳＣ量は実施例１及び２の触媒組成物のＯＳＣ量よりも大きかった。これらの結果から、実施例１及び２の触媒組成物と、実施例３～６の触媒組成物とは、排ガス浄化性能の向上メカニズムが異なることが判明した。 As shown in Table 2, the noble metal dispersities of the catalyst compositions of Examples 1 and 2 are higher than the noble metal dispersities of the catalyst compositions of Examples 3-6, while the catalyst compositions of Examples 3-6 The amount of OSC was greater than that of the catalyst compositions of Examples 1 and 2. From these results, it was found that the catalyst compositions of Examples 1 and 2 and the catalyst compositions of Examples 3 to 6 have different mechanisms for improving exhaust gas purification performance.
　すなわち、Ｃｅ系酸化物粒子がＡｌ及びＭｇから選択される第１追加元素を含む場合、Ｃｅ系酸化物粒子の耐熱性が向上し、Ｃｅ系酸化物粒子の比表面積の低下及びそれに伴うＣｅ系酸化物粒子への触媒活性成分の埋没が抑制され、これにより、排ガス浄化用触媒組成物の比表面積が向上するとともに触媒活性成分の分散度が向上し、排ガス浄化用触媒組成物の排ガス浄化性能が向上すると考えられる。 That is, when the Ce-based oxide particles contain the first additional element selected from Al and Mg, the heat resistance of the Ce-based oxide particles is improved, the specific surface area of the Ce-based oxide particles is reduced, and the resulting Ce-based The burial of the catalytically active component in the oxide particles is suppressed, thereby improving the specific surface area of the exhaust gas purifying catalyst composition and improving the degree of dispersion of the catalytically active component, thereby improving the exhaust gas purification performance of the exhaust gas purifying catalyst composition. is expected to improve.
　また、Ｃｅ系酸化物粉末がＬａ、Ｐｒ、Ｙ及びＮｄから選択される第２追加元素を含む場合、貴金属元素担持後のＣｅ系酸化物粒子の酸素貯蔵能が向上し、これにより、排ガス浄化用触媒組成物の排ガス浄化能が向上すると考えられる。 Further, when the Ce-based oxide powder contains a second additional element selected from La, Pr, Y and Nd, the oxygen storage capacity of the Ce-based oxide particles after supporting the noble metal element is improved, thereby purifying the exhaust gas. This is thought to improve the ability of the catalyst composition for exhaust gas purification.
〔試験例２〕
　試験例２では、Ａｌ及びＭｇから選択される第１追加元素の含有量に関し、好適な範囲を決定するための試験を行った。 [Test Example 2]
In Test Example 2, a test was conducted to determine a suitable range for the content of the first additional element selected from Al and Mg.
（１）試験例２Ａ
　硝酸アルミニウム水溶液（ＡｌのＡｌ２Ｏ３換算量：０．１ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９９．９ｇ）を添加した点を除き、実施例１と同様にして、試験例２ＡのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９９．９質量％、ＡｌのＡｌ２Ｏ３換算量：０．１質量％）を得た。 (1) Test Example 2A
Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 99.9 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 0.1 g). A 2A Ce-based oxide powder (amount of Ce converted to CeO2 : 99.9% by mass , amount of Al converted to Al2O3 : 0.1% by mass) was obtained.
（２）試験例２Ｂ
　硝酸アルミニウム水溶液（ＡｌのＡｌ２Ｏ３換算量：２．５ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９７．５ｇ）を添加した点を除き、実施例１と同様にして、試験例２ＢのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９７．５質量％、ＡｌのＡｌ２Ｏ３換算量：２．５質量％）を得た。 (2) Test Example 2B
Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 97.5 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 2.5 g). A Ce-based oxide powder of 2B (amount of Ce converted to CeO2: 97.5% by mass , amount of Al converted to Al2O3 : 2.5 % by mass) was obtained.
（３）試験例２Ｃ
　実施例１で得られたＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＡｌのＡｌ２Ｏ３換算量：５．０質量％）を、試験例２ＣのＣｅ系酸化物粉末とした。 (3) Test Example 2C
The Ce-based oxide powder obtained in Example 1 (amount of Ce in terms of CeO 2 : 95.0% by mass, amount of Al in terms of Al 2 O 3 : 5.0% by mass) was subjected to the Ce-based oxidation of Test Example 2C. It was made into a powder.
（４）試験例２Ｄ
　硝酸アルミニウム水溶液（ＡｌのＡｌ２Ｏ３換算量：１０．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９０．０ｇ）を添加した点を除き、実施例１と同様にして、試験例２ＤのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９０．０質量％、ＡｌのＡｌ２Ｏ３換算量：１０．０質量％）を得た。 (4) Test Example 2D
Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( CeO2 equivalent amount: 90.0 g) was added to an aluminum nitrate aqueous solution ( Al equivalent to Al2O3 amount: 10.0 g). A 2D Ce-based oxide powder (amount of Ce converted to CeO2: 90.0% by mass , amount of Al converted to Al2O3 : 10.0% by mass) was obtained.
（５）試験例２Ｅ
　硝酸アルミニウム水溶液（ＡｌのＡｌ２Ｏ３換算量：２０．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：８０．０ｇ）を添加した点を除き、実施例１と同様にして、試験例２ＥのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：８０．０質量％、ＡｌのＡｌ２Ｏ３換算量：２０．０質量％）を得た。 (5) Test Example 2E
Test Example _ A 2E Ce-based oxide powder (amount of Ce converted to CeO2 : 80.0% by mass , amount of Al converted to Al2O3 : 20.0% by mass) was obtained.
（６）試験例２Ｆ
　酸化セリウム粉末を大気中１０００℃で１時間焼成し、試験例２ＦのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：ほぼ１００質量％（＞９９質量％））を得た。 (6) Test Example 2F
The cerium oxide powder was sintered in the atmosphere at 1000° C. for 1 hour to obtain a Ce-based oxide powder (amount of Ce converted to CeO 2 : approximately 100% by mass (>99% by mass)) of Test Example 2F.
（７）Ｃｅ系酸化物粉末の平均粒子径の測定
　試験例１（１）と同様にして、試験例２Ａ～２ＦのＣｅ系酸化物粉末の平均粒子径を測定した。測定結果を表３に示す。 (7) Measurement of Average Particle Size of Ce-Based Oxide Powder The average particle sizes of the Ce-based oxide powders of Test Examples 2A to 2F were measured in the same manner as in Test Example 1(1). Table 3 shows the measurement results.
（８）Ｃｅ系酸化物粉末を使用した結晶子径の測定
　試験例２Ａ～２ＦのＣｅ系酸化物粉末を使用して、試験例１（２）と同様にして、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径を測定した。測定結果を表３に示す。 (8) Measurement of crystallite size using Ce-based oxide powder CeO in Ce-based oxide particles in the same manner as in Test Example 1 (2) using the Ce-based oxide powders of Test Examples 2A-2F The crystallite size of 2 was measured. Table 3 shows the measurement results.
（９）ＢＥＴ比表面積の測定
　カンタクローム社製　ＱＵＡＤＲＡＳＯＲＢ　ＳＩを使用して、Ｎ２ガス吸着法により、試験例２Ａ～２ＦのＣｅ系酸化物粉末のＢＥＴ比表面積を測定した。測定結果を表３に示す。 (9) Measurement of BET specific surface area The BET specific surface areas of the Ce-based oxide powders of Test Examples 2A to 2F were measured by the N 2 gas adsorption method using QUADRASORB SI manufactured by Quantachrome. Table 3 shows the measurement results.
Figure JPOXMLDOC01-appb-T000003
Figure JPOXMLDOC01-appb-T000003
　表３に示されるように、試験例２Ａ～２ＥのＣｅ系酸化物粉末のＢＥＴ比表面積は、試験例２ＦのＣｅ系酸化物粉末のＢＥＴ比表面積よりも大きかった。これらの結果から、Ｃｅ系酸化物粉末における第１追加元素の酸化物換算量の好適な範囲は、Ｃｅ系酸化物粉末の質量を基準として、０．１質量％以上２０質量％以下であることが判明した。 As shown in Table 3, the BET specific surface areas of the Ce-based oxide powders of Test Examples 2A to 2E were larger than the BET specific surface areas of the Ce-based oxide powder of Test Example 2F. From these results, the preferable range of the oxide conversion amount of the first additional element in the Ce-based oxide powder is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide powder. There was found.
〔試験例３〕
　試験例３では、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される第２追加元素の含有量に関し、好適な範囲を決定するための試験を行った。 [Test Example 3]
In Test Example 3, a test was conducted to determine a suitable range for the content of the second additional element selected from La, Pr, Y and Nd.
（１）試験例３Ａ
　硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：０．１ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９９．９ｇ）を添加した点を除き、実施例１と同様にして、試験例３ＡのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９９．９質量％、ＬａのＬａ２Ｏ３換算量：０．１質量％）を得た。 (1) Test Example 3A
Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( Ce in terms of CeO2: 99.9 g) was added to an aqueous lanthanum nitrate solution (La in terms of La 2 O 3 : 0.1 g). A 3A Ce - based oxide powder (amount of Ce converted to CeO2: 99.9% by mass , amount of La converted to La2O3: 0.1% by mass) was obtained.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＡのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3A was used instead of the Ce-based oxide powder of Example 1.
（２）試験例３Ｂ
　硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：２．５ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９７．５ｇ）を添加した点を除き、実施例１と同様にして、試験例３ＢのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９７．５質量％、ＬａのＬａ２Ｏ３換算量：２．５質量％）を得た。 (2) Test Example 3B
Test Example was carried out in the same manner as in Example 1, except that cerium oxide powder ( Ce in terms of CeO2: 97.5 g) was added to an aqueous lanthanum nitrate solution (La in terms of La 2 O 3 : 2.5 g). A 3B Ce - based oxide powder (amount of Ce converted to CeO2: 97.5% by mass, amount of La converted to La2O3: 2.5 % by mass) was obtained.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＢのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3B was used instead of the Ce-based oxide powder of Example 1.
（３）試験例３Ｃ
　実施例３で得られたＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９５．０質量％、ＬａのＬａ２Ｏ３換算量：５．０質量％）を、試験例３ＣのＣｅ系酸化物粉末とした。 (3) Test Example 3C
The Ce-based oxide powder obtained in Example 3 (amount of Ce in terms of CeO2: 95.0% by mass, amount of La in terms of La2O3: 5.0% by mass) was subjected to the Ce - based oxidation of Test Example 3C . It was made into a powder.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＣのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3C was used instead of the Ce-based oxide powder of Example 1.
（４）試験例３Ｄ
　硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：１０．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：９０．０ｇ）を添加した点を除き、実施例１と同様にして、試験例３ＤのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：９０．０質量％、ＬａのＬａ２Ｏ３換算量：１０．０質量％）を得た。 (4) Test Example 3D
Test Example was carried out in the same manner as in Example 1 , except that cerium oxide powder ( CeO2 equivalent amount: 90.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 10.0 g). A 3D Ce - based oxide powder (amount of Ce converted to CeO2: 90.0% by mass, amount of La converted to La2O3: 10.0% by mass) was obtained.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＤのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3D was used instead of the Ce-based oxide powder of Example 1.
（５）試験例３Ｅ
　硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：２０．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：８０．０ｇ）を添加した点を除き、実施例１と同様にして、試験例３ＥのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：８０．０質量％、ＬａのＬａ２Ｏ３換算量：２０．０質量％）を得た。 (5) Test Example 3E
Test Example was carried out in the same manner as in Example 1 , except that cerium oxide powder ( CeO2 equivalent amount: 80.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 20.0 g). A 3E Ce - based oxide powder (amount of Ce converted to CeO2: 80.0% by mass , amount of La converted to La2O3: 20.0% by mass) was obtained.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＥのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3E was used instead of the Ce-based oxide powder of Example 1.
（６）試験例３Ｆ
　酸化セリウム粉末を大気中１０００℃で１時間焼成し、試験例３ＦのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：ほぼ１００質量％（＞９９質量％））を得た。 (6) Test Example 3F
The cerium oxide powder was sintered in the atmosphere at 1000° C. for 1 hour to obtain a Ce-based oxide powder (amount of Ce converted to CeO 2 : approximately 100% by mass (>99% by mass)) of Test Example 3F.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＦのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3F was used instead of the Ce-based oxide powder of Example 1.
（７）試験例３Ｇ
　硝酸ランタン水溶液（ＬａのＬａ２Ｏ３換算量：３０．０ｇ）に酸化セリウム粉末（ＣｅのＣｅＯ２換算量：７０．０ｇ）を添加した点を除き、実施例１と同様にして、試験例３ＧのＣｅ系酸化物粉末（ＣｅのＣｅＯ２換算量：７０．０質量％、ＬａのＬａ２Ｏ３換算量：３０．０質量％）を得た。 (7) Test Example 3G
Test Example was carried out in the same manner as in Example 1 except that cerium oxide powder ( CeO2 equivalent amount: 70.0 g) was added to an aqueous lanthanum nitrate solution ( La equivalent to La2O3: 30.0 g). A 3G Ce - based oxide powder (amount of Ce converted to CeO2: 70.0% by mass, amount of La converted to La2O3: 30.0% by mass) was obtained.
　実施例１のＣｅ系酸化物粉末に代えて、試験例３ＧのＣｅ系酸化物粉末を使用した点を除き、実施例１と同様にして、粉末状の触媒組成物を得た。 A powdery catalyst composition was obtained in the same manner as in Example 1, except that the Ce-based oxide powder of Test Example 3G was used instead of the Ce-based oxide powder of Example 1.
（８）Ｃｅ系酸化物粉末の平均粒子径の測定
　試験例１（１）と同様にして、試験例３Ａ～３ＧのＣｅ系酸化物粉末の平均粒子径を測定した。測定結果を表４に示す。 (8) Measurement of Average Particle Size of Ce-Based Oxide Powder The average particle sizes of the Ce-based oxide powders of Test Examples 3A to 3G were measured in the same manner as in Test Example 1(1). Table 4 shows the measurement results.
（９）Ｃｅ系酸化物粉末を使用した結晶子径の測定
　試験例３Ａ～３ＧのＣｅ系酸化物粉末を使用して、試験例１（２）と同様にして、Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径を測定した。測定結果を表４に示す。 (9) Measurement of crystallite size using Ce-based oxide powder CeO in Ce-based oxide particles in the same manner as in Test Example 1 (2) using the Ce-based oxide powders of Test Examples 3A to 3G The crystallite size of 2 was measured. Table 4 shows the measurement results.
（１０）ＯＳＣ量の測定
　試験例１（５）と同様にして、試験例３Ａ～３Ｇの触媒組成物のＯＳＣ測定をＣＯパルス法で行った。測定結果を表４に示す。 (10) Measurement of OSC amount In the same manner as in Test Example 1 (5), the OSC of the catalyst compositions of Test Examples 3A to 3G was measured by the CO pulse method. Table 4 shows the measurement results.
Figure JPOXMLDOC01-appb-T000004
Figure JPOXMLDOC01-appb-T000004
　表４に示されるように、試験例３Ａ～３Ｅの触媒組成物のＯＳＣ量は、試験例３Ｆ及び３Ｇの触媒組成物のＯＳＣ量よりも大きかった。これらの結果から、Ｃｅ系酸化物粉末における第２追加元素の酸化物換算量の好適な範囲は、Ｃｅ系酸化物粉末の質量を基準として、０．１質量％以上２０質量％以下であることが判明した。 As shown in Table 4, the OSC amounts of the catalyst compositions of Test Examples 3A to 3E were greater than the OSC amounts of the catalyst compositions of Test Examples 3F and 3G. From these results, the preferable range of the oxide conversion amount of the second additional element in the Ce-based oxide powder is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide powder. There was found.
１Ａ，１Ｂ・・・排ガス浄化用触媒
１０・・・基材
１１・・・筒状部
１２・・・隔壁部
１３・・・セル
２０，２０ａ，２０ｂ・・・触媒層 1A, 1B... Exhaust gas purifying catalyst 10... Base material 11... Cylindrical part 12... Partition part 13... Cells 20, 20a, 20b... Catalyst layer

Claims (7)

  1. 　Ｃｅ系酸化物粒子と、Ｃｅ－Ｚｒ系複合酸化物粒子と、貴金属元素とを含む排ガス浄化用触媒組成物であって、
    　前記Ｃｅ系酸化物粒子が、Ａｌ、Ｍｇ、Ｌａ、Ｐｒ、Ｙ及びＮｄから選択される少なくとも１種の追加元素を含み、
    　前記Ｃｅ系酸化物粒子におけるＣｅのＣｅＯ２換算量が、前記Ｃｅ系酸化物粒子の質量を基準として、８０質量％以上であり、
    　前記Ｃｅ系酸化物粒子における前記少なくとも１種の追加元素の酸化物換算量が、前記Ｃｅ系酸化物粒子の質量を基準として、０．１質量％以上２０質量％以下であり、
    　前記Ｃｅ－Ｚｒ系複合酸化物粒子におけるＣｅのＣｅＯ２換算量が、前記Ｃｅ－Ｚｒ系複合酸化物粒子の質量を基準として、５質量％以上９０質量％以下である、排ガス浄化用触媒組成物。     A catalyst composition for purifying an exhaust gas containing Ce-based oxide particles, Ce--Zr-based composite oxide particles, and a noble metal element,
    The Ce-based oxide particles contain at least one additional element selected from Al, Mg, La, Pr, Y and Nd,
    The CeO 2 equivalent amount of Ce in the Ce-based oxide particles is 80% by mass or more based on the mass of the Ce-based oxide particles,
    The amount of the at least one additional element in the Ce-based oxide particles in terms of oxide is 0.1% by mass or more and 20% by mass or less based on the mass of the Ce-based oxide particles,
    A catalyst composition for exhaust gas purification, wherein the CeO 2 equivalent amount of Ce in the Ce—Zr-based mixed oxide particles is 5% by mass or more and 90% by mass or less based on the mass of the Ce—Zr-based mixed oxide particles. .
  2. 　前記Ｃｅ系酸化物粒子におけるＣｅＯ２の結晶子径が、１０ｎｍ以上である、請求項１に記載の排ガス浄化用触媒組成物。 2. The exhaust gas purifying catalyst composition according to claim 1, wherein the crystallite size of CeO2 in said Ce-based oxide particles is 10 nm or more.
  3. 　前記貴金属元素が、前記Ｃｅ系酸化物粒子及び前記Ｃｅ－Ｚｒ系複合酸化物粒子に担持されている、請求項１又は２に記載の排ガス浄化用触媒組成物。 The exhaust gas purifying catalyst composition according to claim 1 or 2, wherein the noble metal element is supported on the Ce-based oxide particles and the Ce-Zr-based composite oxide particles.
  4. 　前記貴金属元素が、Ｒｈ及びＰｔから選択される、請求項１～３のいずれか一項に記載の排ガス浄化用触媒組成物。 The exhaust gas purifying catalyst composition according to any one of claims 1 to 3, wherein the noble metal element is selected from Rh and Pt.
  5. 　前記Ｃｅ系酸化物粒子の平均粒子径が、０．１０μｍ以上１５μｍ以下である、請求項１～４のいずれか一項に記載の排ガス浄化用触媒組成物。 The exhaust gas purifying catalyst composition according to any one of claims 1 to 4, wherein the Ce-based oxide particles have an average particle size of 0.10 µm or more and 15 µm or less.
  6. 　前記排ガス浄化用触媒組成物における前記Ｃｅ系酸化物粒子の量が、前記排ガス浄化用触媒組成物の質量を基準として、１．０質量％以上である、請求項１～５のいずれか一項に記載の排ガス浄化用触媒組成物。 6. The amount of the Ce-based oxide particles in the exhaust gas purifying catalyst composition is 1.0% by mass or more based on the mass of the exhaust gas purifying catalyst composition, any one of claims 1 to 5. 2. The exhaust gas purifying catalyst composition according to 1.
  7. 　基材と、前記基材に設けられた触媒層とを備える排ガス浄化用触媒であって、
    　前記触媒層が、請求項１～６のいずれか一項に記載の排ガス浄化用触媒組成物で構成されている、排ガス浄化用触媒。     An exhaust gas purifying catalyst comprising a substrate and a catalyst layer provided on the substrate,
    An exhaust gas purifying catalyst, wherein the catalyst layer comprises the exhaust gas purifying catalyst composition according to any one of claims 1 to 6.
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JP2017189761A (en) * 2016-04-11 2017-10-19 トヨタ自動車株式会社 Method for producing catalyst for exhaust purification

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US20240149252A1 (en) 2024-05-09
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